For me - IWB is really about three things.
1. Leather - a sturdy leather holster that supports the gun is a must.
2. A sturdy leather gun belt to support both the holster and gun.
3. Gun - for me, smaller is better when I carry IWB. I usually carry a Smith 637. The gun is light weight and easy to conceal.
"He who laughs last, laughs dead." Homer Simpson