" I did more damage as kenetic then i ever would as infiltration " and that where you are going wrong, of course you will last longer and feel like you are actually doing some thing ( I out last alot of tank and hybrid spec's with my dps spec ), in reality you are doing fluff damage that any good healer will compesate for. Total damage doesnt mean any thing if you don't kill any one.
I also take into consideration how peeps play, so my play style might not match yours but my personal opinion is that Deception is better. Play as deception with a team that can gaurd you, heal you and assist you, you will feel worthy and helpful, trust me IF! and only IF! you know how to play deception spec.