First of all, MK3 got butfucked with the recent patch, it isn't a MK3 anymore. Even Firefox is better.
AMD's accuracy got nerfed and the bloom has increased. I don't know about the other 2 but I suggest you AK-107.
famas mk3. ace 3 rounds with that gun... but im a experienced tapper/burster. so i suggest the 107 for ya if yer new. if you can afford para GET it. it currently rapes. just try to aim and not spray past 4 shots.