I managed to get my ff/dark up to 23 over the weekend, and am quite enjoying him now. They synergy of the sets is great, especially post-SOs. Your build is pretty similar to mine with a few differences. I'de suggest picking up maneuvers earlier, as while its defence aint that high on its own, combined with your bubbles and dispersion field, thats reaching the soft cap of defence, 45% with SOs. I got maneuvers at 18 and am leaving getting fly till 24, (temp travel powers really helped). Maneuvers also helps your defence too, which is always good.
As yet undecided about detention field and blackstar (often cosidered the worst 'nuke' in the game).
So ide get maneuvers earlier, at least by 24, but otherwise, your build looks pretty good.
This is now the build im trying with SO slots, no IOs as of yet 
Hero Plan by Mids' Hero Designer 1.30
http://www.honourableunited.org.uk/mhd.php
Bethany-Rose: Level 50 Magic Defender
Primary Power Set: Force Field
Secondary Power Set: Dark Blast
Power Pool: Flight
Power Pool: Fitness
Power Pool: Leadership
Power Pool: Medicine
Ancillary Pool: Power Mastery
Hero Profile:
Level 1: Personal Force Field -- DefBuff(A)
Level 1: Dark Blast -- ToHitDeb(A), ToHitDeb(9), ToHitDeb(11), Acc(42), Acc(43), RechRdx(43)
Level 2: Deflection Shield -- DefBuff(A), DefBuff(3), DefBuff(3)
Level 4: Gloom -- ToHitDeb(A), ToHitDeb(5), ToHitDeb(5), Acc(9), Acc(11), RechRdx(13)
Level 6: Insulation Shield -- DefBuff(A), DefBuff(7), DefBuff(7)
Level 8: Hover -- DefBuff(A)
Level 10: Swift -- Flight(A)
Level 12: Dispersion Bubble -- DefBuff(A), DefBuff(13), DefBuff(15), EndRdx(15)
Level 14: Fly -- Flight(A)
Level 16: Tenebrous Tentacles -- ToHitDeb(A), ToHitDeb(17), ToHitDeb(17), Acc(19), Acc(19), RechRdx(23)
Level 18: Health -- Heal(A)
Level 20: Stamina -- EndMod(A), EndMod(21), EndMod(21)
Level 22: Night Fall -- ToHitDeb(A), ToHitDeb(23), ToHitDeb(27), Acc(27), Acc(33), RechRdx(33)
Level 24: Maneuvers -- DefBuff(A), DefBuff(25), DefBuff(25), EndRdx(34)
Level 26: Tactics -- ToHit(A), ToHit(33), ToHit(34), EndRdx(34)
Level 28: Aid Other -- Heal(A), Heal(29), Heal(29), RechRdx(31), RechRdx(31), IntRdx(31)
Level 30: Aid Self -- Heal(A), Heal(36), Heal(36), RechRdx(36), RechRdx(37), IntRdx(37)
Level 32: Resuscitate -- Empty(A)
Level 35: Detention Field -- Acc(A), Acc(37), Acc(39), RechRdx(46)
Level 38: Blackstar -- Acc(A), Acc(39), ToHitDeb(39), ToHitDeb(40), RechRdx(40), RechRdx(40)
Level 41: Power Build Up -- RechRdx(A), RechRdx(42), RechRdx(42), ToHit(43), ToHit(46), ToHit(46)
Level 44: Temp Invulnerability -- ResDam(A), ResDam(45), ResDam(45), EndRdx(45)
Level 47: Life Drain -- ToHitDeb(A), ToHitDeb(48), ToHitDeb(48), Acc(48), Acc(50), RechRdx(50)
Level 49: Total Focus -- Acc(A), RechRdx(50)
------------
Level 1: Brawl -- Empty(A)
Level 1: Sprint -- Empty(A)
Level 2: Rest -- Empty(A)
Level 1: Vigilance
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Opinions?
Oh man, I've got a level 26 Forcefields/Dark but I can't give any advice...you obviously aren't into the other half of the Forcefields primary, which was the part I was focusing on. Of course, accuracy debuffs don't stack with knockback, so for synergy it makes sense. Then again, ignoring half of your primary lets you freaking super-focus on pool stuff, which is pretty cool...lord knows there have been times when I wished I had more of the Medicine set.
-jared
Yeh when I was figuring out my build, I thought "Hey, im leaving out half my powers on both my primary and my secondary!" I then realised, I'm not that big a fan of knockback, especially in teams (which my toon is purely for) and I know it can be used well, but well, i'm not one of those that can. So I was left with an awefull lot of power slots free. Ok, so manooovers is a given, so might as well get tactics and maybe veng. Could use a heal, so ile get aid other and aid self, and might as well get rez to go with veng as well. Makes the build nice and loose really when you leave out the knockback stuff. Might pick up force bolt for entertainment perposes, but otherwise, the knockback would be usually counter productive to the 2 cones of dark blast, as keeping them tight becomes more important. So I sacrificed some control for better damage and better teaming utility.
Not saying the knockback powers are bad, but for a ff/dark, they make less sense I guess.
If you only snag one of the knockback Forcefield powers, I'd suggest the knockback aura. I have it running when I team 100% of the time and it's like providing a "safe zone" for the blaster who's trying to get away from the melee mob that he's [censored] off. I haven't been hit by a melee attack since level 18 since I picked it up and when you have a decent amount of ranged folks on the team, it's a great way of keeping the enemy from engaging.
Just my 2 cents. Force Bolt is fun, but the Aura is freaking useful. Just don't charge in with it on or the tanker will beat you silly for it.
-jared
Ahh yeh good point. Had forgotten about that power. Yeh its one im likely to pick up at some point. For now my PFF is my panic button power. Doesn't help the rest of the team much when it goes pear shaped, but at least it gives me time to get out of there!
to be honest i'd pick forcebubble over repulsion field (if that was the name, forgot sorry ), not only is repel greatly superior to knockback, but the range is bigger as well meaning that blaster will never have to get in melee if he doesnt want to. Also i found that repulsion field's ticks of knockback were too slow and too end heavy.
Downside of forcebubble is that when used badly, it will make a spawn really really really [censored] at you. Meaning that all that ranged damage will kill you instead 
As for detention field, i found little use for it in PvE. Solo you should be able to manage most foes, and in teams it often works more as a nuisance to your teammates than anything else.
Considering the build, it looks fine to me tbh. Though i'd try to squeeze at least 1 endreduc in both insulation shield and deflection shield (otherwise casting it on a full team will leave you with no end), and at least 2 endreducs on dispersion field.
"god, how many devs did hami have to sleep with to get ED?"
Total Cat @Stagefright
To clarify, what exactly is the effect of forcebubble, is bassically a kin's repel but a larger area?
[ QUOTE ]
To clarify, what exactly is the effect of forcebubble, is bassically a kin's repel but a larger area?
[/ QUOTE ]
Force Bubble is 'real' repel (like TK) unlike Repel which is actually k-back (like Repulsion Field). Make sense? 
CoX 50s: <ill/rad> <ice/ice> <fire/kin> <grav/sonic> <ice/storm> <earth/kin> <kin/elec> <cold/psy> <thugs/dark> <fire/dark> <dark/elec> <night widow> <EM/ninj> <mind/icy>
Forcebubble is a huge PBAoE repel power, kin's repel is a knockback power. While they got similar effects (repel and kb), there are a few minor differences.
First of all, they are 2 different effects. Meaning that even if you got kb resist from acro, you dont have repel resist. People often think its the same, but its not.
Second of all, repel doesnt necessarily fling a foe on his back. It will just push something away. A minor detail, but with great effects. It means repel is less useful for damage mitigation than knockback, aside from the fact that repel is useful for damage mitigation cause ranged damage is generally less than melee damage.
Hope that clarified something a bit, if not.. if you're on union drop me a line and stage'll show you forcebubble
"god, how many devs did hami have to sleep with to get ED?"
Total Cat @Stagefright
Totally see where you're coming from. I'm planning on grabbing both, but from experience on Villains I know that if you have Force Bubble teaming with folks who need melee range means not using it as often as you'd like. With the Repulsion (KNockback aura) Shield, I can be subtle in providing a safe spot for the blasters to...err...blast from. As long as I don't charge in, the melee toons have very little to complain about. Then again, if your whole team is ranged, NOTHING beats Force Bubble.
Now that I'm building a Force Field toon on Heroes, I'm sort of dreading getting Force Bubble. Just a little. There are so many people who literally will abandon a team if it doesn't have a tanker and since Force Bubble sorta screws with the whole herding process....don't know. Should be interesting finding a place for it in those stereotypical teams that show up from time to time.
-Jared
Ive recently started this FF/Dark defender as the though of the +def and -acc interested me a lot. Ive read a few other posts and have devised this build, theres no slots put down so far, but slotting advice is welcomes
*TKLD(JA'.9W^IY
Hero Plan by Mids' Hero Designer 1.30
http://www.honourableunited.org.uk/mhd.php
Bethany-Rose: Level 48 Magic Defender
Primary Power Set: Force Field
Secondary Power Set: Dark Blast
Power Pool: Flight
Power Pool: Fitness
Power Pool: Medicine
Power Pool: Leadership
Ancillary Pool: Power Mastery
Hero Profile:
Level 1: Personal Force Field -- Empty(A)
Level 1: Dark Blast -- Empty(A)
Level 2: Deflection Shield -- Empty(A)
Level 4: Gloom -- Empty(A)
Level 6: Insulation Shield -- Empty(A)
Level 8: Hover -- Empty(A)
Level 10: Swift -- Empty(A)
Level 12: Dispersion Bubble -- Empty(A)
Level 14: Fly -- Empty(A)
Level 16: Tenebrous Tentacles -- Empty(A)
Level 18: Health -- Empty(A)
Level 20: Stamina -- Empty(A)
Level 22: Night Fall -- Empty(A)
Level 24: Aid Other -- Empty(A)
Level 26: Aid Self -- Empty(A)
Level 28: Resuscitate -- Empty(A)
Level 30: Maneuvers -- Empty(A)
Level 32: Tactics -- Empty(A)
Level 35: Detention Field -- Empty(A)
Level 38: Blackstar -- Empty(A)
Level 41: Power Build Up -- Empty(A)
Level 44: Temp Invulnerability -- Empty(A)
Level 47: Life Drain -- Empty(A)
Level 49: Total Focus -- Empty(A)
------------
Level 1: Brawl -- Empty(A)
Level 1: Sprint -- Empty(A)
Level 2: Rest -- Empty(A)
Level 1: Vigilance
<font class="small">Code:[/color]<hr /><pre>| Copy & Paste this data chunk into Mids' Hero Designer to view the build |
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</pre><hr />
Thanks a lot for reading