I currently own, or have recently owned, carried and fired a S&W 640, Ruger SP-101, and a Taurus 650 and 651. All of them work well and have been good performers for me. I have no problem in relying upon and carrying either revolver.
If you at all anticipate any pocket carry, then go for the 640 or the Taurus 650 or 651. In my view, the SP-101 is somewhat too large and heavy for pocket carry.
On the issue of quality control, every manufacturer can turn out a lemon from time to time. You can see posts complaining about all three manufacturers if you look long enough. The odd thing, however, is that there are fewer complaints related to functionality of the SP-101, although many people complain about the fit and finish. In my opinion, the S&W and Rugers of today are not as well-made as the models that I bought new in the 1980's. All of my Taurii were manufactured in 2004 and I bought them new, so I have no previous models to compare them too.
I have approximately 18 handguns in my safe right now, and the ones I carry most frequently are either the 650 or titanium 651. Make of that what you will.