I split my time between the two.
Honestly, Caesars "regular" rooms are much nicer than "regular" Bellagio rooms.
Better bathrooms (separate WC, jetted tub, everything better).
Especially since the re-decoration of Bellagio rooms...ick.
Note this was not a "remodel" as they say, just a re-decoration.
But that is only my opinion and preference for Bel's old classic decor vs their new cowboy-meets-lava lamp decor. Many will like it I'm sure.
But I love a lakeview room at Bellagio, for the fountain view.
If you can score a corner room at Bel, much better. Excellent bathrooms.
Of course if you can score a suite at Bellagio, differerent story also.
But I've never had a real suite at Caesars, and only a salon suite at Bellagio, not really a suite but nice big room.
Overall, I like the casino atmosphere at Bellagio, and definitely the tables.