While I was loading War Rock I realised that it had the same HackShield as Combat Arms (mum these are both first person shooter games) and both have the problem with hackers. I found, last time I played Combat Arms, there were a lot less hackers than War Rock.
The graphics for Combat Arms are better War Rock's, possibly because War Rock is older. By better I mean: I think the scenery in Combat Arms was maybe a little more detailed; but also the guns look better.
CombatArms has a larger variety of game modes than War Rock. For example I loved quarantine mode. In this mode there is a maximum of 16 players on the server all on 1 team; there is a 20 second timer and once that timer gets to 0 a proportion of players will become zombies - and for up to the next 3 minutes the zombies try to convert everyone else that is trying to stay alive. How to stay alive? RUN... RUN...RUN. Or: have everyone team up in a room and just defend with mines, flamethrowers, machine guns, shotguns and sniper rifles. I say those weapons because they are the most effective. Or I've seen some people just blow themselves up with bombs - chickens.
CombatArms has a larger variety of weapons that you can get without actually spending real life money. I liked the SCAR because it did good damage at short and medium range with good accuracy and the G36E which performs even better damage than the SCAR but can also scope and was a bit more accurate.
Another good thing about CombatArms is that you dont have to pay for maps.