I have stayed at the Hotel Monte Carlo Las Vegas numerous times, and I'm ready to move on to other hotels. Its outdated, the food at the main cafe and buffet are so-so, however the rates were pretty fantastic. Compared to the other hotels, especially the newest arrivals, it shows its age.
However, I do like it that the concierge will put hotel guests on the VIP list to get into Haze, and other nightclubs in the vicinity. That was a cool feature we appreciate, and at no cost to the concierge for to get in.
If its deals you are looking for, and "decent" rooms, it is worth looking into.