The enhanced sensors of ed-e is a bonus but the mean reason I take him over rex is that the noise rex makes when running drives me nuts.
I would say boones perk is more useful then his high guns skill. Having enemies glowing red when its night time and you are taking a long distance sniper shot is brilliant.
I have given him all sorts of weapons for CQC (I leave him with his hunting rifle for long range as its good enough and doesnt take ammo). He is equally good with melee as well, as someone above mentioned he seems to love using "oh baby". He is amazing with a riot shotgun up close too but burns through ammo really quickly.
He does make it harder to get some achievements (he tends to steal a lot of kills) and he does tend to mess up my sneak approach a lot of times by just charging in head first.
I have tried veronic, rex and the ex-enclave guy but couldn't really get on with them as much. I will go back to them at some point just to do the quests but dont think I will use them long term.
