I had a PSS on my boat when I purchased it. It leaked, most likely because it wasn't installed properly. Even worse was the allen set screws in the collar were rounded out. So I had to cut the shaft out of the boat, not an easy feat on a Sabre 28. This has left me with a bad feeling about he PSS even though I know a lot of people are very happy with them. I just felt stuck with no way to stop the leak and the only fix was a 4" angle grinder with a cut off disc to get the shaft out. If you can't remove the collar you can't remove the shaft.
I switched to a regular stuffing box with Duramax Ultra-X stuffing. I feel safer knowing I have more flexibility of managing an issue with the standard stuffing box. I do all of work myself but I also think a PSS might be a bid too complicated for a regular mechanic that wants to get in an out.
I think it was Maine Sail who recommended using a collar from McMaster-Carr to backup the PSS collar for safety. It's a little cleaner than a zinc or the hose clamp that was on my shaft. McMaster-Carr
Just my opinion,