I've been to the Melting Pot a few times, and while I enjoyed the food, atmosphere, and service I'm of the opinion that it is overpriced. It's definately (for someone on a budget) one of those places that you only go to for special occasions. If you view it as an "experience" (like Habachi at Mori/Osaka) it's kind of unique and lends itself to occasions like birthdays, anniversaries, graduation, prom/formals, etc. Expect to spend at least $35 a person for a full dinner for two (appetizer, main course, and dessert) without drinks/tip. The service is always good, but I would avoid nights like local Prom, Graduation, and Valentine's because it is usually packed (if you're planning to go on these nights, call a few days ahead and ask if they are taking reservations).
Occasionally I like with my friends and have the dessert (chocolate fondue with a variety of fruits, cookies, and cake to dip into the chocolate). I think this runs about $15 - 20 for two and is a nice treat for someone's birthday or just to pamper the chocolate lover in your life.