I have a PX4 as well. I have only carried it once. I have been trying to find something comfortable and nice. I have a XD45 with a comptac holster and I like that. But I have been thinking on OWB carry.
So not wanting to spend a lot of money on a holster type that I would not like. So I went and bought a Fobus paddle holster. It is comfortable and the gun "clicks into the groves". However it moves around a little bit and it is a 25.00 dollar holster. So I plan to use it some more to get a better feel for that type of carry if I decide to carry that way then I will spend better money on quality.