I don't have experience with the Cobra but I've owned several SP101s. They've been reliable for me. I think they are attractive guns. As others have said, they really do benefit from better grips. The Hogue Hardwood grips are a godsend but do add size. My only reason for keeping stock grips on any of them is probably silly. I've got some custom grip panels that I really like. =P
I can say that modern SP101s don't look as nice or as well made as older ones. For whatever improvements, the newer ones just seem rougher. My last SP101 had an especially bad DA trigger. The cylinder bound up within the first hundred rounds and I had to take it in.
My gunsmith told me that the problem was caused by a bur. He expressed further disappointment after examining the internals. Apparently, the crown as off center too. I could have sent it back to Ruger but I said "what the heck". I had my gunsmith recrown the barrel, do a full trigger job, polish the internals, chamfer the cylinders, and add a trigger stop for the over-travel. Now it's better than stock. Unfortunately, the trigger is still not as smooth as a very lightly shot model from twenty years ago.
One thing I didn't fix and wish I had was the side-play in both the hammer and the trigger. There is much more slop there than in older models. At some point, I'll get around to installing shims. I probably won't buy another Sp101. I've been much happier with the LCR and I hope they'll continue to develop the 3" LCRX line.
