I usually always come here to watch movies when I'm visiting Vegas. My fiance lives near Santa Fe Casino, but their movie theatre (Century) is just not as nice as going to Red Rock Casino and Regal.
First of, this movie theatre is inside Red Rock Casino. Seriously one of the nicest resorts I've been to! The interior design is so nice and elegant. You'll definitely feel like first class here. (:
Anyways onto Regal Cinemas. The box office service is a hit or miss. Sometimes you'll get service that sucks because they don't want to be there so they're stalling time or you get the ones who are enthusiastic and show they actually care about service.
The movie theatre. CLEAN, COMFY SEATS, and adjustable arm rests (isn't that always a plus?). Big screens, comfortable audio level, though it can get chilly. If you have a theatre that's closer at the end of the hall (usually the movies that have been out for a while), you may want to make sure you use the restroom and get snacks before hand. There is no snack bar in the middle or restrooms in the middle of the hall. You'll have to track on back all the way to the beginning of the theatre hall.
Food: Concession stand is always expensive. I haven't been stopped for bringing in casino food court food in. Though my friend has been stopped once on grand opening night. So if you go during down time, they don't mind if you bring in food or drinks from outside it seems like.
For grand opening day of movies, they're pretty organized about where the line is and who was in line and kind of checks for people who cut and what not. Which is nice.
They often do donations for charity during big premieres. (: