Good post. I had a 3" GP100 for CCW but it was much too bulky and even with a stout belt, felt like it was yanking my trou down.I don't have a ton of experience with the 101, but here is my take - the GP is like a tank, big and heavy and powerful. The SP is more like a jeep or humvee, smaller and lighter and more portable. The SP is way more concealable, the GP is more of the gun to keep next to your bed but way harder to conceal.
Hope that helps.
Sold it and got a 3" SP101, much better. Now I have that and a 6" GP100, a barrel that really gets makes use of the performance of the .357. Don