I switched to free aim recently (a few days ago - a week at the most), and it's horrible. People are massively more aggressive than in auto aim sessions, and I'm not saying this after just 1 session so please don't give me the "it was just a bad session" excuse. People actively hound you in packs for literally no apparent reason (they obviously have a reason, but it's lost on me). There are a lot more people in Rhinos, Buzzards and Lazers and they're out to cause grief. The only sessions I've been in since changing that haven't been like this are the ones where there's only 2 other people in there, which admittedly happens more than not.
I need to change my playing style and start doing deathmatches if I want to get better with free aim, because at the minute I'm not getting chance to pull the trigger that often so I'll never get better. It's not easy to get the upper hand when you've got a group of 3, 4 or 5 people spawn killing you, and that seems to be the norm.
Unless something changes drastically, I'm gonna have to say free aim sucks. I do okay using free aim when doing gang attacks or in missions, so I'm obviously not totally sh*t. It's just the aggressive attitude that is rife in free aim sessions that is very unpleasant. Seriously, it's a different game and I don't think I like it.