I have stayed at Circus Circus several times over the years. It is a decent hotel with the basic amenities, in a slightly more kid friendly environment than the other hotels. The pool is not the scene that it can be at times with the other hotels though.
I would suggest using priceline.com or hotels.com etc to get a hotel, I have done that and ended up here for all but one of my Circus Circus stays. It is an older hotel with a different ambience than many of the other casinos.
There is a shuttle that will take you from one end of the strip to the other cheaply that leaves from here multiple times a day as well as cabs cruising up and down the strip. If you like to get in a workout, its a nice walk to work out those sore muscles after a car or plane ride to some of the other hotels.
The pool is bare bones basic. The casino is reasonable but nothing that I play too much at. The midway shows are fun for all and no other hotel has the free circus/midway acts that they do here. They also have the kid allowed gaming area which is a fun place even for adults to enjoy.
Definitely an acceptable place to stay when you get a deal on a room of $50 or less a night (usually on the weekends too).