I like the store. Reminds me of buying a pack of cards, wondering what you'd find inside. I'm gonna play more on the PC demo, but there was a more expensive pack. I'm guessing there's greater reward there for buying that one instead of four 5k credit packs.
I played as a drell vanguard briefly and I like that animations are changed up. The drell does backflips for dodge and kung fu kicks for melee.
One thing it might have over normal horde modes is that it seems to shuffle objectives for each wave. At least that's how it came off in the one or two rounds I played. It would've been nice if it had point to point co-op levels too, like Uncharted 2/3, Battlefield 3, MW2, and a couple other games.
And I dislike how close the camera is to the character. I lost track of the enemy I attacked after doing my vanguard boost, even though he was right next to me.