Well, in the first place, the combination of cards is the only thing that is the same in these two types of poker. As far as I know, there is only a pot-limit of Omaha, unlike Hold'em, which can be either a pot-limit or without a limit. I believe that if a person likes poker, he will become a good player in any variation of this game. But Omaha and Hold'em are two completely different games, with their own characteristics and nuances.