Pokerstars has the tightest PLO tables across all limits. Play is still pretty weak at the lower limits, though.

Take a look at PokerStars PLO right now, where there are 5 or 6 25PLO tables running with avg pots between $4 - $8. Now at the same time there are about 20 games going on Party, most of which have an avg pot over $10, some as high as $20.