I loved Adam Sandler growing up. I saw nearly all his movies at the theater after first seeing Billy Madison on VHS, and he was just by far my favorite comedic actor. Being grown up now... I must admit I stayed a fan of a lot of his work. I can watch Happy Gilmore and Billy Madison anytime and still be entertained. But at the same time, shit like Big Daddy and Waterboy are fucking ******ed to me, and I loved those movies back in the day.
Overall though, I think Adam Sandler is pretty great. Sure he does some stupid fucking shit from time to time (Mr. Deeds, I Now Pronounce You Chuck and Larry, ect.) but films like Reign Over Me, Punch-Drunk Love, Anger Management and Click more then make up for it. I thought all those films were amazing. Also, I can't wait for Funny People and that has the potential to be spectacular as well.
As far as Will Ferrell is concerned... he's hit or miss for me. For example, I recently watched his George Bush stand-up HBO Special and Semi-Pro for the first time, and both were absolutely shit. However, I also saw Step Brothers not to long ago and loved it. And then you have movies such as Wedding Crashers, Old School, and Talladega Nights that are all tremendous/hilarious, but then you have Blades of Glory, Bewitched, and Stranger Than Fiction... which are all fucking terrible. So, my overall opinion on him is that he's very inconsistent with his work. Sometimes he makes me laugh, and sometimes he wants me to commit suicide for sitting through his crap. Very hit or miss with me as I said.
And as far as Ferrell and Sandler working together? Eh, not too sure if the chemistry would be right. But I'm sure it would draw and it wouldn't hurt to try. I'd most likely check it out if it were to happen, but my expectations wouldn't be up.