For me, the M4A1 would have to be my favorite rifle and the beretta for a pistal. Can’t beat a silenced auto weapon and a pistol with 20 rounds in it. 
True the m4 and beretta use 9mm rounds and lack the punch of some of the other rifles and pistols, but they fire so *edited* fast it makes up for it.
The M4 is evil for headshots and people without armor too.
So far as hating a weapon, its not so much the weapon as the user, but a noob with an awp who thinks its fun to sit in spawn and just blast at people across the map. -.-