Pve players will play halo and come back there is more to do but I feel alot of pvp players will leave for halo though, there really isn't any contest between the two pvp games. Have not seen any lag so far,(sounds small but makes a big difference to the experience) rewards skill and has no mercy for the poorer players. You have power weapons but no op guns to start with. If you want a competitive pvp, arena is where it's at :)