I always wanted a 4" .32 H&RM SP-101... then, a couple of years ago, I found one unshot LNIB. Previously, I had owned a myriad of SA & DA Rugers - this was the worst, QC-wise. Sure, it was 'improved' - with a lot of TLC. It was the straw, however - I finally said goodbye to all of my Rugers except for one - a c&b bp revolver. I bought more S&Ws with the moola I got from my Ruger sales.
The SP-101 I had was equipped with a cheesy windage-only adjustable rear sight. It was slightly larger than a J-frame, like a 60 or 63. It just didn't have the quality of construction, obviously from all of the burrs I had to ease, that a S&W would have. It was simple to break down - but needed it more often. The trigger was better than my only J-frame - a 642 - but only after new springs and a lot of work. The 642 is stock (It's my CCW - the .32 SP101 was for play.).
The 'last straw' with the SP-101 - and SA SSM I had in .32 H&RM - was the over-sized chambers. They worked the .32 brass - even at my plinker loads - making the SP-101's ejection difficult. The Hogue monogrip helped the grip - by comparison, even a 5" 63 - like the current one I want - needs a larger grip for my use, too.
It is decidedly smaller than my 2" 10 or, of course, my 6" 66 - and now my 4" 617 - my K-frame collection. So - put it between a J and K-frame. Better yet, put it back - get either a J-frame (60) or K-frame - you'll have a lot nicer revolver. I'm not opinionated, of course.
Stainz