Be aware though, I run a version of Domination that allows for AI recruitment just to make it a little more balanced for us because there's only 2 or 3 of us playing a map vs 60+ infantry and 20 or so armor on every town.
Most MP servers don't allow the AI mod and you have to rely on teamwork from other players with limited communication - for instance, you'll rarely ever get another medic player to heal you. There are occasions where you'll get your legs chopped out so if you attempt to move you'll instantly go prone and the only way to recover from it is to have a medic patch you up or respawn/die.
In scale, it's massive - there's nothing you can really compare it to in terms of other popular shooters that you may have experienced in the past. It does help if someone can show you the ropes though. I used to play ARMA a long time ago and even playing ARMA2 online took me a little time to get accustomed too. Recently I've been playing a lot of Operation Flashpoint and going for a run last night after about a 3 week break, I was a little rusty.
Nothing beats whacking a BTR90 from 600 meters with a SMAW though.
