I use IWB's exclusively. I just haven't found a better way to carry, stripped down to shorts and a T-shirt in the summer. Shoulder rigs and OWB's require some kind of cover shirt at a minimum, and I'd rather not. Ankle holster just ain't practical for my choice of CCW (1911 or clone).
I liked the Nick Matthews holsters for their severe rake; those holsters would cant the grip "almost" vertically, allowing better concealment. It does suffer from a lack of a reinforced mouth, though, making it hard to reholster one-handed. And in this heat, I found that the 'sweat shield' was a little too skimpy also, so I requested a custom-sized shield with mouth reinforcement and got no cooperation there, so I went to AKJ Concealco and he fabricated this:
http://www.concealco.com/miva/merchant.mvc?Screen=PROD&Store_Code=ACL&Product_Code=SG-IWBS&Category_Code=051IWB
He liked it so much he added it to his production line. (I really do have the first 'prototype'). It doesn't have the severe cant that is found on the Matthews holster, but it's constructed better and conceals "well enough" (NM has only been making holsters for ~1 1/2 - 2 years though he's improved a lot since his first offerings) .
I've tried two of the Milt Sparks IWBs--the Watch Six and the VersaMax II--the Six has a flimsy mouth too, and though the VersaMax II solves that problem, it printed because it didn't hold the gun close enough to me. Bulman Gunleather's PDL printed, empty(!!), so I'll sell it whenever I get around to it.
I guess for my money, I'd recommend the AKJ or NM holsters for their ability to pull the gun in towards the body tighter than most.