Free aim is better because every fight in free roam just feels more valuable, not simply who shoots first or who has better access to cover.
Only lame thing about free aim is the assholes who use Entitys as shield, forcing you to blow them up and pay the 10K insurance.
This happens in Auto-aim as well - just had two Entities reverse on me outside LSC (I spawned there and had 5k bounty due to stealing car) but I could do nothing, I blow them up and pay near 20k or get shot, they got me again after I respawned as well, nowhere near my vehicle they just creep up reversing while I can't get away on foot or retaliate... Such fun.
I'm going to try free aim as I had the usual situation yesterday of someone gunning for me, we both hide behind opposite corners of a wall, he steps out - I go to shoot him but immediately rotate 90 degrees to shoot a cop in the face while the other player then guns me down. Absolutely retarded system, where you're facing should have SOME bearing on where you aim!