well, i have a couple wheelsets with IROs, and i am soon building a set with phils.
my IRO hubs have been wonderful. i don't have a bad thing to say about them. however, phils have passed the test of time, and durability is what i'm most concerned about.
the fact that phil now makes cogs is a big plus to me, too. perfect hub/cog/lockring compatibility is a good thing.