Depends on your playstyle, honestly. And since most armor in the game is individual pieces, its even more complicated than that. Except for probably cooldown/power boosters, any other combination will probably work great for you, as long as you pick what works for your needs.
There is no correct answer here. --- Pokemon White Friendcode - 2193-7011-1635 BEEP BEEP RICHIE!
Pound for pound, pretty much all armor is equal in this game. They all give about the same amount of bonus, just to different stats. There is no best or ultimate armor. You find the armor that gives the best combination that suits your playstyle. Take a look at Cerberus armor; do the stats sound like they be good for you? If so, then buy it. There is no bad armor in this game, though I'm sure you could make bad combinations (tons of extra ammo on an Adept who rarely uses guns). --- Pokemon White Friendcode - 2193-7011-1635 BEEP BEEP RICHIE!
I'd say, if you're not going for the individual pieces, either get the Cerberus or Collector Armor. One's better for offense, the other defense. Whichever you feel is lacking or more important, go for it.