I have the 2.25 bbl 101 and really like it with crimson trace laser grips. But, as quite a bit of my carry is in the field and might be used on animals, I've been thinking hard about going to the 3 3/16 for any increased power I might get while still having the CT grips - otherwise I'd opt for my old 4 inch security 6. Might take the 2.25 to the city and leave it there for town use - a little more concealable and a little less need for max power.
I have used the Desantis IWB holster but it worked a big lump on my hip this spring when I carried a heavy knap sack too. The pack must have ridden down on the gun butt. Most field carry is with a Bianchi nylon belt holster.
I sure like the ruggedness of the 101 and its fit in my smallish hand. One thing, I took some emery paper and a medium stone to a lot of the sharp corners and edges of the gun frame trigger and trigger guard. Then a light buffing with crocus cloth and one can hardly tell anything was done except its easier on my hand.