Omaha has a very long way to go before it reaches the status of NLHE (it would take at least the same level of TV exposure, among other things), but with the NLHE games getting tougher, and people naturally exploring other forms of poker, I'm sure it can only increase in popularity.
I personally prefer it to HE; it's more fun, the players are worse (that may include myself, hehe), the pots are bigger, the action more packed, what more do you want?
I find mixed games great as a diversion. When I've gotten bored of playing my main game continuously, when the variance is just killing me, it's nice to turn my clueless
hands to the likes of Stud 8 or Razz. Actually played Badugi for the first time two days ago... Strange, strange game. I'm not sure how useful playing one form of poker is for improving your skills in another form, but I reckon being familiar with these various different forms enhances your general "card sense".