This is an interesting list if one likes the luxury treatment. Link at the bottom.
*Probably the nicest I recall is Bellagio in L.Vegas. I was with a group that included two high rollers and the other four of us in the group were avg. So the casino treated our whole group with extra niceties.
It was a couple levels above my typical room. Though not a penthouse suite or multiple bedrooms suite,..etc.
Another time I was in Tunica and the lady checking me in asked: Would you like an upgrade to a Penthouse luxury suite? Me: Yes that would be OK. :) .
I wasn't a high roller and hadn't given them much action that year. However, I thought it was a classy move (& smart business) on her part. It was during the week. I'm sure they had several luxury rms that were going to be empty anyway.
https://www.888casino.com/blog/worlds-poshest-casinos (https://www.888casino.com/blog/worlds-poshest-casinos)
Continued Success,