Advice on Available Scrappers!

Hi all I have recently returned to the game and been looking through the forums to decide what kind of scrapper to play. Similar to a recent thread posted I was looking for a good all around scrapper, one I can farm on without being horribly slow or inefficient, and also one I could potentially try to solo some AV's on when I get 50 and the right build. I read in that thread fire/shield was voted best with a fire/WP second but my friend plays a fire/shield and my other friend plays elec/shield and I'd rather not copy them. I have 3 scrappers in the 30's and was wondering which if any of them could be made to satisfy my goals above and which would be best at it:
30 Spines/Invul
33 DB/Elec
35 Kat/Elec

I had considered leveling a spines/elec but I don't know if elec is the best for farming with it having zero defense offered through the set and how important defense seems to be nowadays.

Any advice is welcome and will be appreciated!

Thanks for the replies so far, seems as though elec armor is a little squishy when compared to others at least in the 30's which is the only experience I have with it and it seems to benefit a lot from IO slotting from my time spent in mids (although my midfu is sadly underdeveloped). Is this true and would it be able to hit the +2/x8 number I see people mentioning often in the farming posts?
Thanks again for the replies.

Spines with pretty much anything is a good farming primary because you can pick your enemies to match your secondary, and spines does great aoe damage all by itself, even better with more offensive secondarys like DA, elec, and FA. But it has weak single target damage, so you'd have a very hard time soloing AV's regardless of secondary.

The best all around scrapper combo, imo, is fire/SD, though I'm not sure how bad the SC nerf is going to hit the combo. Fire does great single target and aoe damage, and SD gives you additional aoe dmg, and good starting defense so you can reach softcap defense with IO's, and softcap defense is pretty vital if you are going to take down avs.

Having said that, literally any scrapper combo can be built into a pretty respectable all around toon or specialty toon, especially with IO's and using pool powers, so pick something you enjoy and make it work for you. And with the two build option, you could make one build for aoe, and the second build could be your single target build.

Think that was my recent thread that you were refering to, and my Fire/Shield is now at 50 and slotted out with IO's, and soft capped with positional defense.

I'm loving that toon, but I really miss the convenience of the WP set. My two main gripes right now, and they are pretty minor, is that with shields you have to manually activate the resistance to holds/sleep/mez etc.. This is the first toon that I've not had hasten on auto, because I find it far more devastating for that not to be up (running a lot of the rikti mission lines atm). Just means I now have to manually hit hasten every min or two, minor inconvenience, but not something that happens with the WP set.

My other minor concern, even with a pretty expensive decked out IO build is that I just don't feel like my health regeneration during combat is even close to that of a WP build, but this could be something to do with my current build - even so my regen is sitting at 255% (18.6 hp / sec), so it aint shabby. However, when my health dips to the 33% mark, and my green health insps have run out (even with softcapped pos def), I feel less secure than I did with a WP build. Bare in mind here that I'm currently fighting +3/+4 x8 missions solo - so I expect to get clobbered once or twice. Trouble is, if a critter at +3/+4 gets 2-3 hits close together then you're toast, because the regen isn't fast enough to cope. Again, its a minor complaint, and and with the capped defense it doesn't happen often, but it does happen. Granted I could drop to +2/8 and life would most likely be very peachy.

Anyhoo, rambling again, sorry. End result for me is that I'm very very happy with the combination, it farms way faster and safer than my fire/kin controller, and works equally well for teams and solo play.

I'm tempted to try roll a elec/shield next just to compare the two, and finish up my fire/wp as well.

In regards to the incomming "nerf" on the shield charge - I honestly wouldn'y worry about it, fire/shield is a beast and decimates things even without using it.

I havn't tried soloing an AV with this yet, mainly because I'm taking the time to work on some of the accolades to get some extra HP/end etc.. However, it trounces most things I've thrown at it so far.