I have GP100 4.2" 22LR (no longer in production) and I have the 3" LCRX in both 22LR and 22WMR. Love all 3.
The GP100 is the prettiest of the bunch (especially with the Altamont wood grips) I love it's fiber optic sights, the trigger pull isn't bad, and it shoots like a champ, but mine tends to have issues with high velocity ammo shells sticking in the cylinder.
The trigger pull is a little heavier on the LCRX but I have trained to shoot it pretty well, easily hitting 6" plates at 25 yards off hand with consistency.
I have handled the SP101 before and had intended on buying one at one point to pair with an SP101 4/2" 357 I have, but the trigger pull on the one I felt in my LGS was absolutely horrendous so I have since stayed away from them.
The 617 is absolutely beautiful and I will own the 6" version one day...
I like the look of the 63 as well, but I like my LCRX so much that I'm not sure I need another 3" 22 revolver.