I've never used a iwb holster but just about every post and discussion I have heard or read on quality iwb holsters, the Milt Sparks always seems to play a factor.
I could help you more with a owb decision
I have an Andrews Mac II IWB that I absolutely love. It only has one belt loop...but I like it that way. And the cant is adjustable for personal preference. It only took about 3 weeks to get back in Feb.
I ordered two Holsters from Black Hills Leather. One for my 1911 and one for my Kel-tec, then turned around and bought an OWB from Black Hills leather, and have been nothing but happy with all of em. The IWBs were both the same model BH21 I believe. Holster, plus taxes, and S&h was less than 40 bucks.
My two favorites are from K&D Holsters and Andrews Custom Leather. Both make great products that work well for me. Holsters can be such an individual thing. That's why we seem to "need" so many of them....
I had a Sparks a week and sold it . Guy I sold it to did same.
I buy all my holsters for this place. He is new and does good work at a fair price http://ubgholsters.com
He started making holsters for us at my place http://bersatalk.com and has grown from their.