From the Project Reality devs, like a cross of Insurgency and Arma 3 (No vehicles yet at the time of this writing though). So far, one of the best communities I have been in, because everyone coordinates and actually has mics. While not super 1000% realistic Squad has found a very nice niche between Arma and Battlefield.

Note: Be wary though, I have seen many performance problems on the forums, however with my i5-4690k and GTX 970 it runs 40-65 fps on Max settings (While not super amazing, very refreshing compared to Arma 3's performance when playing on 70 player servers just like Squad). Also, if you have an AMD CPU, Unreal Engine 4 is not optimized for AMD CPUs so expect really bad performance until either Epic or Offworld sorts it out.

Update: Three years later, vehicles from logistics to tanks have been added, a bunch more maps including my favorite Al Basrah from Project Reality, fireteams so I can split my Squad so they won't blob up like V9 and below, Squad lock so I can have squads specifically for logistics and tanks, and much much more...

PS.
After your initial burst of hours, don't burn yourself out too much playing while waiting for updates like I did, since the pace of updates has slowed down a bunch from the first year...