I stay regularly at Harrah's--comped there; not elsewhere. But each trip I try to stay at a newly opened resort. I felt that Venetian had the best rooms though their pool was not that much fun. Bellagio is outstanding but I would put it behind the V and Wynn's where I stayed last year. MGM was just too big for me.
Ordinarily I always stay at the Convention Host hotel but this year and last had too many comped rooms at Harrahs not to use. I like the people at the Riv--very friendly and there is the Splash Bar crowd that will waylay you as you leave the convention floor.