I feel like the Monte Carlo deserves more credit than it gets. I recently took a trip to Vegas. Typically I'd stay at the Wynn or Aria but I was traveling with a friend who was trying to stay on a limited budget so we opted for cheaper options and came across a really good deal at the Monte Carlo. I was pleasantly surprised with my experience. While the Monte Carlo is outdated and largely lacks the luxury of hotels like the Wynn or Aria, it was great considering it only cost about a third of any of those hotels. My room was very clean, the staff was as friendly and helpful as can be, and the location is pretty good. I didn't eat at any of the restaurants as none were particularly appealing, and that's probably the biggest drawback. On the plus side, they have Sambalatte Torrefazione which quite easily makes the best coffee anywhere on the Strip. The casino is pretty low key and laid back too, which I did appreciate.
If you're looking for some world class hotel, the Monte Carlo isn't that. But if you want a comfortable stay in a convenient location with a friendly and attentive staff at a great price, the Monte Carlo should be at the top of your list.