There's not much more I can say about this that hasn't already been said, but I want to add my two cents. Melt lives up to and far exceeds the hype. For all the complaints about how busy it is, it is worth every second of wait time.
I am generally skeptical of places that offer "upscale" comfort food, but Melt is the real deal. Nothing about it is pretentious, and the prices are great considering the amount of food you get. I visited Melt four times in my recent two-week visit to Cleveland, and I never once had a bite of food that was less than excellent. Melt is simply my favorite place on the planet.
Go early, or shut up and deal with the wait. It's worth it. Oh, an for the love of God, please don't be one of those people that orders Miller Lite at the bar. Melt has a fantastic selection of beers at reasonable prices to compliment their sandwiches, so take advantage of that.