I received my MarWare CEO Sleeve today and I'm happy to report that it is my favorite holster-style case to-date!
Case: Very attractive leather case with elastic sides that hug the iPhone perfectly! Not too loose and just tight enough to allow some loosening over time yet still be snug enough. Nice contrasting stitching and, what feels to be, flexible plastic under the leather (vs. cardboard) to help retain the shape. Best of all, no ugly company logo on the outside of the case (instead, discretely attached on the back of the case, out of sight when attached to your belt).
Belt Clip: I'm particularly happy with the optional Spring Clip belt clip that I ordered to go along with CEO Sleeve. Although the Spring Clip doesn't accommodate thicker belts, it is, in every other respect, exactly what I was looking for in a belt clip. Fixed vertical position, no ratcheting, and tight up against the case so the case (and iPhone) are held close to the body.
As mentioned previously, the MarWare case use the Multidapt system:
http://www.multidapt.com/products.php
Here are some photos with my iPhone in place so you can see the excellent coverage and just how nicely the Spring Clip attaches to the case.
Two big thumbs up!!
Mark
P.S. If someone eventually does come along with NICE two-piece combo with a nice leather protective shell that protects the iPhone and a nice leather holster that accommodates the iPhone with the leather protective shell on it, that's one I'll consider too!