The no-recoil on the M27 is great, but the time to kill is too slow to make it the "best weapon". If you get into a gun fight, you will lose plenty of times. The best weapon imo would have to be either the MSMC, PDW, or FAL.
Wait I got it! Super Mario 3D Land will be in California and Super Mario 3D World will be in Florida. Zing! ~AloofGuyXXVII