No idea. I've seen it for sale in the local game store too, but nobody has played it.
I've bought the base game, and it's too late for me to put thought into going into detail, but that said...
I think it's a lot of fun. I've played twice, once with a 2-hero game, and once with 5 heroes. Personally, I think that the sweet spot will be a 3-hero game. It gives a short enough time between turns to be fun, and the game isn't too short either. I'll point out that this is an expansion, however...I don't know what comes in it.
Good to know Cydeth, I've never actually played it (even though I bought it and a couple of the expansion packs). I only bought it for the Anime-esque minis for use in a Pathfinder game with my 8-yr. old.