I prefer Omaha.
I feel there are less "bad beats" in Omaha. Before I get five hundred "Your post has been quoted" emails, let me explain. In Omaha, because of the number of hand combinations against you, unless I've got the absolute nuts, I'm always expecting to be beaten. Therefore when I'm beat, there is no way I could call that a bad beat.
Now in Texas Hold'em, it's just the opposite. The number of times I've expected to win, and failed to do so is ............. well I could go on forever. You only need to look at all the posts re bad beats here on Cardschat.