As far as comedy goes, Jim Carrey has always been the better actor. Watch Dumb and Dumber again, and there is a nuiance to his role as Lloyd Christmas that people don't give him credit for. The same goes for The Mask. The Mask is one of my favorite movies (as a superhero movie, not the best of the best, by my standards). He's always been a better actor, Ace Ventura was funny to me until about four years ago, and now I cannot laugh at it, but when Jim does do comedy, he's brilliant, though. He's been a better actor, all together.
He and Adam Sandler's spin in the 90s is like Stallone and Schwartzenegger's stuff in the 80s: It's kind of sad to see him go back to the well, now that everything has sort of changed (we seem to have matured somewhat to this silly schtick that the 90s was in abundance of).
Adam Sandler, though, has been the overall loser in this, which is sad to say. I know he tries to do quality motion pictures at times (Punch Drunk Love is in my top 5 favorite movies), his performance in 50 First Dates, though creepy to some degree, he gives it a lot more heart then most of his movies.
But then, he tries to go for movies that resemble quality, but aren't (I'm looking at you, I Now Pronounce You Chuck and Larry, a failed attempt at what could have been a better movie if only the writers could have been a little bit more mature with the subject matter), and it really disappoints me.
Jim Carrey is an actor I've liked more as I've got older for trying to venture into more uncharted territory (Eternal Sunshine, Number 23 (which I actually like), The Majestic, Truman Show, The Mask, about half of Cable Guy) then Adam Sandler has (Punch Drunk Love, 50 First Dates, Spanglish, Eight Crazy Nights (Which I actually like), about half of Big Daddy), and sadly, I've not seen Reign over Me yet, but it is on my list.
It's disappointing, but it's Adam, and I say that while saying that PDL is one of the best movies I've seen.
EDIT: I forgot Funny People, Click and Hotel Transylvania for Adam Sandler for his other "Not Too Bad" movies.
Forgot A Series of Unfortunate Events, A Christmas Carol, I Love You, Phillip Morris and Man on the Moon for Jim Carrey in his other "Not too Bad/Great" movies.
Thank IMDB for being so through, because I wasn't.
Answer still stands: Adam Sandler isn't quite as great as he should be.