S&D. All strategic, only 100 hp health, and mission is similar to real life. Defusing a bomb. What I think about the other modes:
TDM: No skills, just RUNNNN and spray. If you die you know where they are and RUNN and spray.
Ghost Mode: Requires skill in either pinpointing/bhopping. However, lots of noobs ruin it by coming in with m60s or spas (can't pinpoint/too easy for them to kill ghosts)
FreeForAll: People spawning RIGHT behind you = unfair/ annoying.
Elimination Mode: Great for trying out weapons, but team has to fight over weapons. Columbia is okay, but the map structure is meh. Too small/too little places to hide.
Mutant Mode: When theres alot of people mutants always win and get more kills. When there is less people only one mutant and he gets gang banged.
Escape Mode: Fun, but its similar to TDM.