People always come to me to ask where to eat in Vegas that is a good meal without breaking the bank. Mon Ami Gabi is always on that list.
The food is French Bistro. They do a great job with all the French standards. Nothing too flashy, but consistently good. The steak frites was good. Really enjoyed the cheese surrounded by tomato sauce thing. Mon Ami Gabi even does a pretty descent brunch with make your own bloody mary bar.
One thing Mon Ami Gabi has that is worth it is spectacular views of the Bellagio fountains. So try to get a seat by the street for the best view.
If Picasso across the street is way out of your price range, and you want some classic French food, Mon Ami Gabi is a solid choice.