H4's Multiplayer is very fun. It's mostly well balanced aside from the Death Star -- I mean, DMR. People are right when they say it feels like Halo... it does. But there's no heart to it. It can be fun, but there is no, shall we say, Fort Knox. The money is where the mouth is, but the money is counterfeit. It just feels... wrong.
Halo Reach was actually overall pretty balanced. There were issues, like the banshee and such, but there was a soul to it.
Another thing--Halo 4 had no innovation in terms of Forge. In fact, other than magnets, all that was done was remove Forge World.
Which was, needless to say, a horrible idea.
Reach has the same Forge as 4, yes; but at least it innovated. It did not mimic.
The file share in H4 is broken as hell. Reach was not.
Halo4 has barely any custom games. Reach had many.
REACH WINS.