Monte Carlo has been discussed on these boards many times since I've been watching these boards. It tends to often get overlooked since it is not a loud, flashy property. It's a decent place to stay & I have enjoyed it many times over the years. Not a bad location on the strip, room prices are usually very reasonable (they often have special promos available), and it has the free monorail to City Center & Bellagio now as well. Some have complained about noisy rooms, but I've never personally had that problem there. Many of those complaints were during the initial stages of building City Center alongside it, so that may have had something to do with it.
Most unfortunate part is that wart called Diablos that was stuck onto the front of what was a nice looking hotel. Avoid Diablos like the plague - unless you're a frat boy since that's the crowd that seems to inhabit it. Diablos food & service are both generally awful & the atmosphere is not much better. On the other hand, the Pub on their Street of Dreams is a really good place to spend an evening - big screen sports all over and a fun place to spend time. Brand Steakhouse is a nice place to eat if you are looking for a little more upscale meal.
Casino is smaller & quieter than many others around that area of the strip. I have found the dealers at Monte Carlo to be a very pleasant group - maybe because of the overall low key atmosphere in this casino?
Keep in mind, however, it is one of the MGM properties, so they do charge the "dreaded" resort fees in addition to your room price.