i m completely destroying holdem at the moment but fail and just breakeven at omaha, sample size can definitely be an issue though. i also feel the players at holdem are predictable and bad whilst i rarely find very clear bluffing spots in omaha (blocker bluffs aside). also just a little more than half the hands per table at omaha and i still can play less tables...
so i gotta say i think omaha players are better than holdem ones.
i used to struggle at holdem cash games and used to beat omaha in the past though. i feel that nowadays the omaha games are so high variance that you need to be very good mentally or hugely overrolled to take the variance.
i also think the omaha has helped me a lot in developing my holdem game which just seems much simpler to me.