I have an SP101 in .22 and while a VERY nice gun-it does not replace my 63. If I had to get rid of one-the 101 would go based on the trigger pull and lighter weight. The SP101 is more akin to the 617 4" . Tough choice here as well, but I would keep my 617 because of the nice trigger.
The SP went back to Ruger when I bought it because the trigger was abysmal and what I got back was as nice a trigger as one has a right to expect from a Ruger. It is still not on par with the 63 or the 617 (or the 317-1 or k22 for that matter). The trigger IS better than my 317.
I flat out like the Ruger a lot I like how easy it is to take one down if it gets dunked in salt water and how well it's built-but it is not, nor ever claimed to be a Smith and I wouldn't sell one of my Smiths to buy one.
Tell you something else about Rugers, I also like my Super Redhawk and my SP101 in .357 too
