Just to add few things. 
Good 
Iron sight  no cross hair in this game
Authentic weapons  each performs as should with good sound effects. 
Damage model  It takes only one bullet to kill (depends on cal, distance, etc)
Human like movements  no bunny happin' counter strike sh%t here, 
Maps  most beautiful maps Ive seen in any mod
TeamKill  Makes it more challenging when you have to ID enemy by uniform. Sever that I play allows 3 TKs. If other player forgives you for TK then you can kill more then 3 (affects score, officer -6 points, -4 MG, -2 solder)   
Balance  each side gets certain amount of unit types, so entire server is not full of snipers and MG.  
Mission objective  each map has its objectives so this is not just a death match. 
Bad 
Servers - few good servers, (only server I play is (CiA))
Tanks  damage model sucks but sometimes are fun to just mess around. 
Bugs  couple bugs are still in the game but they are not show stoppers.