We'll have to take their word for it (as we haven't played that many minis games before), but the game was a lot of fun when we played a round of it at BlizzCon last year -- it's kind of a mix between turn-based strategy (in that you take turns moving your characters and attacking or defending) and Arena play (in that lots of the character abilities are borrowed straight from the ingame classes). We can speak to the quality of the game as well -- the little miniatures look great, and the game boards and cards were very colorful and well-done.
So grats to Upper Deck for picking up the Diamond Award for their new minis game (the company also nabbed a few other awards for their Marvel Masterpieces cards and their sports card lines). If you'd like to check the game out, you can pick up starter packs at most hobby and game stores, and Upper Deck periodically offers events around the country. Some of which we often post about here on WoW Insider, so stay tuned.