It was more like 4 1/2 stars, since our stay wasn't flawless. In my opinion this was among the most aesthetically pleasing casinos in Vegas.
It's not cheap, but our room was top notch. One of the most overused (but true) cliches is "You get what you pay for". The room was spacious, exceptionally clean, and we had an awesome view of the strip from our window. However, my favorite feature was the giant jacuzzi tub with large roman tapestry designs on each size (I'm a sucker for large bathes).
My only minor complaint was with the room service. Our breakfast was about 15 minutes late and they forgot our sides. I know that sounds a little nit-picky, but for the price paid for the service, I felt it needed to be flawless.
I also appreciated the large fountain and aquarium in the shopping area and all the roman replica statues and busts. The casino/shopping area have a lot cool little details so be sure to look around.
Overall, if the opportunity arose I'd be thrilled to stay here again.