Umbral

Well, first things first, Charged Brawl does a good deal more damage than Boxing and takes less time to animate. Looking at raw damage doesn't tell you much, especially if you consider attacks like Total Focus or Eagles Claw. They may deal a lot of damage in a single blow, but they're horrible for DPS because they've got cripplingly long animation times. A better metric of comparison is damage per animation time (DPA). Charged Brawl has a DPA of 54.7 (57.8 damage / 1.056 seconds), and Boxing has a DPA of 35.98 (47.5 damage / 1.32 seconds) (if those animation times look longer than you're used to seeing, I can explain Arcanatime). Now, 54.7 compared to 35.98? It becomes rather obvious which is better.

Now, in the Kick v. Boxing argument, DPA matters less because they're both atrocious attacks (35.98 compared to 26.57). All the power will really do for your build is sit there looking pretty, get you access to Tough and Weave, and, potentially, mule an IO set. As a set mule, Boxing wins hands down because Absolute Amazement is absolutely awesome, and even Stupefy is significantly better than any of the KB sets. No one should be using either of them as an attack (if you're optimizing).

First things first, change your attack slotting. Hecatomb should go into Storm Kick (your best attack) rather than Eagles Claw (your worst). You should also think of getting rid of Eagles Claw in favor of Crippling Axe Kick for the simple fact that they've both got pretty much the same DPA (which is lower than Crane or Storm Kick for both of them) which means you'll spend less animation time doing sub par DPS (re: Storm>Crane>Storm>CAK is better than Storm>Crane>Storm>Eagles). Just as well, the 6 piece Hecatomb set is largely pointless. Get rid of the Hecatomb Damage and you'll be able to save a slot to put elsewhere.

Similarly, you went a bit heavy on the +rech set bonuses. MA isn't all that recharge intensive. Once you get Storm Kick down to a 1.848 sec recharge (225% +rech), that's all you really need. The global +rech will provide you with all the +rech needed to get Crane Kick and Crippling Axe Kick recharged fast enough (3.96 secs for each; i.e. 153% +rech and 103% +rech, respectively). You can then use all of the slots that you'd be saving on wonderful things like +hp and +regen (which will allow you to go without using the DPS castrating Aid Self for longer periods of time)! You might also want to consider putting a couple slots into Tough to actually enhance the +res value. As strange as it may seem, a little bit of +res is actually quite effective on an */SR.

First of all, Hover has no tohit penalty associated with it being active. That's kind of the point: it's combat flight. The only power within the flight pool that has a tohit penalty is Group Flight, but that only applies to your nearby allies.

Second, Personal Forcefield isn't really going to be turned into a personal shield power in the vein that you speak of specifically because it would be so easy to circumvent (unless you're talking about a giant tohit debuff such a -75%, at which point it begs the question of why even bother allowing the ability to attack). It's not an issue of "pros and cons". It's a question of balance.

Third, the "best" FF build is highly debatable, especially if you're talking about a build or simply a powerset combination. Where builds are concerned, the question of what you're trying to accomplish is going to have a large enough impact on the state of "best" that it's impossible to simply state a single build is best. For powerset combinations, it depends on what kind of synergy you're looking for. */Sonic provides offensive advantage and has synergy in the sense that FF/* has very low animation time requirements. */Dark provides synergy in the form of -tohit to compliment FF/*'s +def (though, the -tohit isn't that spectacular against harder targets, nor is it particularly useful when you consider how easy it is for FF/* to softcap everyone with only Maneuvers).

Here's an IO build I've got for FF/Sonic. It's softcapped to range, can softcap all allies indefinitely, runs the Shriek>Scream>Shout attack string, and is infinitely endurance sustainable with WoC turned off. It's probably not going to be the best for soloing (though it will do so quite admirably), but it'll be an incredible force multiplier on teams (not to mention that it'll make everyone on your team nigh upon unkillable).