Only played a few hands, but here's how I've got the players pegged:
Brock: Very Loose, Slightly Passive. Will often check and call down with bad hands, but rarely bets them. (Honestly, I wouldn't expect that Brock would be the worst player, but it is what it is.)
Claptrap: Tight Aggressive. So far, Claptrap IS the best player at the table, bar none. He really is smart, and he's not getting out of line with crazy cards, so far as I can see. His problem is that he can't read Ash and Brock well at all, and as a result is folding way too often to their (to me) obvious bluffs.
Ash: Loose VERY Aggressive. Ash will bet it he's got a hand. Or if he doesn't have a hand. Or if he thinks you don't have a hand. Or if he thinks you have a hand that he can get you off of. Or if he sees a woman. Or if his evil hand twitches. Sadly, because Claptrap and Sam are playing tight, and Brock's just got no clue, he usually ends up winning most pots.
Sam: Tight Passive. Sam's waiting too long for good cards. If this were a deepstacked cash game, Sam would probably be cleaning up, but considering that this is a tournament, with only 50 big blinds, where players tend to wildly overbet the pot (rare even in NLHE, and just plain *stupid* in Omaha, which is why it's played pot-limit in most cases...) Sam just can't adjust.
By the way, Omaha suffers the most from the "50BB" starting stack. Omaha is practically designed to be a deepstacked game - because the starting hands are so close together, you turn a five street game into a preflop game. And omaha's starting hands run so close together, you might as well flip coins if you're getting it all in preflop.