Mhm, you really should play against Collectors or Geth on 60fps. Or even better... 120fps host with laggy internet. 
If a Collector Captain shoots at me, then my shields are gone. 600 base shields vs. 990 with full fitness (QFE) is not much of a difference on Gold and above.
It makes no difference. 60fps enemies react quicker but lolconsole movement is so much worse that you spend a lot more time exposed, and if anything the enemies hit you more often. You can't control the camera so large portions of time are spent awkwardly moving your character at combat walk speed to face the correct direction, and you also can't modify the sensitivity except for by using adrenaline mods (because it is somehow tied to movement speed).
If anything, fitness is more useful on lolconsole. I do fine without it, sinful's just a scrub. Most mooks do anywhere from 120-150 damage per shot on gold, so quarian fitness is good for tanking 2-3 extra rounds......from enemies with machine guns that fire 10+ rounds per second. How useful.
It'd be a lot better if cyclonics weren't simply a base modifier and had less absurd percentage increases in general, but as of now the only real useful feature of fitness shield specs on anything that doesn't have a DR power is the 15% recharge, which is normally too expensive for the small benefits that it brings. Not even the oft cited 990 threshold really means much of anything, because most gold heavy hitters do more damage than that per shot, nevermind on plat where even Phantoms do well over 1000 damage per shot.
It's great if you're still learning the game, but otherwise should only be specced into if other powers bring less benefit than rank 5. The QFE's turret and passives are not one of these cases IMO.