Not so sure!
Firstly I want so say great review Troggie - everything you say is spot on.
I like the epik holster, but I'll be sticking with the oem holster.
One of the reasons I got the epik holster was because I thought that it would be easier/faster to get the phone in and out of with one hand.
Getting the phone out of the holster with one hand is a bit tricky. You raise the clip and use the thumb to push the phone out, and then you have to grab the phone and pull out and make sure you don't drop it (which I've almost done a few times). I find myself using both hands more often than not to get the phone out safely.
And I find that getting the phone into the holster with one hand is really tricky, especially if you are wearing a shirt that falls past and covers the holster. First of all, you have to be really careful to actually place the phone properly in the bottom brackets. Then you have to raise the clip and push the phone in and push the clip down snugly. I find that my shirt is often getting caught somewhere amongst the holster, phone and clip, and when I pull the material out, the clip often comes up and the phone can come loose.
In comparison, I can easily get the phone in and out of the oem holster with one hand, shirt hanging over it or not, and the phone never seems at risk of being dropped.