Came by for lunch the other day. Compared with the Aria, the catering is light years ahead. The shrimps that we had for our salad were huge compared to the ones at the Aria.
The meat quality of the steak was also top notch.
Lastly, the main difference at the Bellagio compared to the Aria is the better air quality (less dry) and the seats that are breathable with real leather (vs. the pleather at the Aria)