Ended up buying this guy, too much fun!
Bought Alarak and Fenix before this, and got Stukov from SC:R. Fenix was something of a misstep, was before F2P so i didn't get to test him first. Still pretty fun, but probably wouldn't have bought him if i had tried him out. Stukov has been my favorite so far, love the combined zerg/terran style along with ridiculously massive army. And Alarak's just plain hilarious.
Wish Blizzard could make new commanders faster. There's a ton of characters who'd be interesting. Heck, might throw in some villains as well! Mengsk, Duran (human, not Narud), DuGalle (in as much as he was a villain) would be rather interesting. Then there are good guys left, like Tassadar, Razagal. Yeah, dead, but that's evidently doesn't matter, for Tychus and Zeratul are in.