I'm in line for a Milt Sparks PMK -- basically an Askins Avenger for revolvers. It will take half a year, but should be worth it. They really iron their holsters out. It's molded to the last detail.
I get the logic of pancake designs -- they spread the weight out -- but they take up a lot of waistline real estate. Pretty much belt loop-to-belt loop. My jury is out on a thumb-break. It's one more thing to think about if you have to draw (like a 1911 thumb safety...) but if you go upside down for any reason, it's a good thing. I'm using a Don Hume 715 open top right now; not because it's a great design, but because it could be found!