I was recently gifted a new M&P 9mm Compact and needed a holster. I've used a number of holsters over the years and decided to try something unique (which usually ends up in me buying something terrible).
In this case, I made a great decision. I picked up an 'original' holster from N82 (er, N8^2) Tactical (n82tactical.com). It's an IWB holster made with a combination of neoprene and leather. I'm here to tell you it is the most comfortable IWB rig I've tried to date. The backing gives easily when you reach to unholster the firearm allowing an easy full grip on the gun when grabbing it from the holster.
I wasn't sold on the single-clip design. I've had similar models like that before (High Noon Split Decision, I believe) and found it to be a tad unbalanced. This one seems to work rather well.
The only downside is, with the original model, you can't reholster one-handed. They do have a professional model that uses kydex (I assume) for a specific gun mold that would make single handed reholstering no problem. The original version ($39+$3 shipping as of right now) is plenty good enough for me. There's also a tuckable version of similar design. Such a simple design, but dang if it isn't the most comfortable thing I've tried...