Nothing special. Just like other mentioned, they are like Denny's happened to be at the Bellagio. If you are Denny's kind of person, this is a place for you but be ready to pay Bellagio price.
They prioritize seating for Mlife members but not for the hotel guests. You will be asked to be in the same line with bunch of other random tourists just visiting for the conservatory. Noisy!! You are expected to get fed and go.
If you are staying at Bellagio, go to the Pool cafe which only opens for the hotel guests. They are soooo much better than this Denny's.