I've been to Charlie's On Main quite a few times now... My first experience being my very first Yelp event in Madison!
Since that first time, Charlie's has been on my list for bringing out-of-town guests who I know will just love seeing the speakeasy door open and really appreciate the cocktails. I don't think I've ever ordered something I didn't like, although I can't recommend anything that will knock your socks off. I have had several times when the kitchen was out of a particular ingredient or dish(es), which can be disappointing.
One of the things that I really like about Charlie's is the full vegetarian/vegan menu that they offer. It makes it really easy for people who want a veggie option to make a choice knowing exactly what they're going to get.
The last time I was there, I ordered chocolate cake for dessert and asked if I could have ice cream on top. Holly, our server, actually grabbed her wallet and walked next door (despite my protests!) to get ice cream to serve with the cake. This is the kind of extra service you'll get at Charlie's that I really enjoy.