Nothing is wrong with Circus Circus its just a lower end hotel but its an incredible value most of the time. Its the best value on the strip otherwise you'd have to go to downtown "old" Las Vegas to get the same rate but everything is a 10-15 dollar cab ride away.
Not sure what deal you have but you can check out more
Las Vegas Promotional Codes for the Circus Circus promo code:
The prices don't really drop lower than what is advertised and or what you can get with a promo code.