Melt in Mentor is great if you want a grossly huge grilled cheese with more than the works. The prices are decent but on each occasion I have dined in, the atmosphere is very different (read: more family oriented, dull, typical) than the other locations in Lakewood and Cleveland heights. I think this has less to do with the business itself and more to do with the general population of Mentor (I am from Mentor and when I want to go out and find a good crowd I am not doing it in my hometown).
Long story short: Go if you want a lot of food and to give a huge Melt sandwich a try. Don't go if you want a lively atmosphere.