About one year ago, I had one done on my model 25-5 in conjunction with a cylinder replacement. It took about three weeks out and back.
The work (besides the new cylinder) was:
1. Trigger Stop
This was a roll pin drilled into the back of my nice case color target trigger. It was ground off on an angle such that it met the frame at a point, and was not deburred, had grinding flash still on it. I thought it would be an internal stop, which the gun already had. They took the internal stop out and returned it to me.

2. Chamfer Charge Holes - OK

3. Polish Rebound Spring, Hammer Stud and Yoke Barrel Bosses - OK

4. Detail Lockwork Surfaces. The polish looked like it was done by just jamming the entire inside-the-frame part of the hammer and trigger into a buffing wheel rather than detail contact areas like the raised pin bosses. All the case color was gone, and pin bosses could no longer be seen as separate surfaces from the body of hammer & trigger. The hammer now has side play in the frame and rubs on one side. No shims were installed to center the hammer.
The machine marks on the frame where the rebound slide moves were untouched.

5. Stone Hammer and Trigger Contact Areas. When I sent it, the gun had the usual wonderfully crisp S&W break from the factory. Because of the apparent jamming of the hammer & trigger in the buffing wheel, I can't tell if they overstoned the single action sear or buffed off the crisp edge. It now has very unsatisfactory creep in the single action trigger pull.

6. Test Fire for Function - I can tell this was done because the clean gun I sent Smith came back covered with fingerprints and powder residue.

In the process of doing all this, they scratched the side plate with a screwdriver slip next to the screw at the cylinder and rolled up the edge of the side plate near the hammer.

I realize now the 'Master Action Job' is primarily for double action use of the revolver (my bad), and a "Master" did not work on my gun (their bad).

The only good thing I can report is that the double action pull, though heavy, is very smooth and the cylinder locks up nicely very early in the trigger stroke.

I had heard so many good reports here about the Performance Center work, that I had high hopes for being delighted.
I'm really, really disappointed.

Before you all jump on me for not going to right back to Smith, health issues commencing just a couple days after the gun was returned to me, and continuing over the past year, have not allowed me to test fire the gun, and I would not feel right going back to Smith not having done at least that.