The Speed Six is a wonderful weapon. The grip does not control magnum recoil very well for me, unless I use an oversized grip that covers the backstrap, and this makes the gun bigger than I want; I prefer an open-backed grip/stocks that leave the backstrap exposed.
That being said, I really do like my 4" Speed Six, with an open-backed Pachmayr Compac Professional grip, a superbly balanced engineering equation. Load for load, an SP101 controls recoil better, but the Speed Six has better practical accuracy. My Speed Six fills a useful niche between my SP101s and GP100s, just as a K-frame fills a niche between J-frames and L-frames.
I don't carry my Speed Six often, as my wife, uh, requisitioned it. That is OK; I have plenty of other 4" handguns, including a SWEET S&W Model 19-5, and GP100s. I do have my eyes open for another 4" Speed Six, of course.
I prefer the 4" Speed Six. The snubbier ones don't give me any more barrel than an SP101, and a 3.06" SP101 is another one of those perfectly-balanced engineering equations.