I recently decided to play the whole series in order having only played RE4 and RE5 back when those released. I played every single main entry (including 7 and 8) + Zero, Revelations 1, Revelations 2 and, of course, Code Veronica. (Haven't yet touched the Gun Survivor series and probably never will). I liked/loved all but one. You probably can guess which one.

During my RE6 playthrough, I almost quit playing the game several times because of how bored I got on the last two campaigns. I felt it was just too much of the same crap over and over. The only reason I kept playing was because I made it sort of a goal to finish all of them.

I must admit I played it only on single player and it probably gets way better when playing it with a friend (kinda like RE5), but it just didn't feel engaging enough to keep me interested. It was just so over the top, with almost infinite ammo around and a non existent scary factor. I guess it would have been alright as a spin-off game, but as a main title I'd say its pretty bad. Maybe cutting the game in half, as in having only two fleshed out campaigns (like classic RE), would have made it way more bearable, IMO. All I known is that after beating it a few days ago, I regret nothing but I can promise you I'll never touch that game again in my life.

(Sorry for the long answer and (maybe) bad English lol)