I think your post offers some good insight of what is wrong with PSS. It is just to sensative. We are sailors, not astronauts that are highly educated and trained to go on Apllo missions to the moon.
I want equipment on my boat that can be abused, not installed perfectly, can be overused beyond is "designed" capability, can be beat on and ask for more.
I worked on subs and what impressed me is how basic and strong these things are made. They are made for an 18 year old out of high school with a little training to be able to make work.
PSS is just to sensative for the average sailor. And I want no little plastic fittings on my boat holding back the sea.
There's nothing "wrong" with the PSS shaft seal -- you just have to know how to use it --- like so many other things on a sailboat. I've had the PSS shaft seal on BR for over 10 years with no problems.
Sailors, like astronauts, have to do things the right way. The use of the set screws is one the things you have to get right if you use the PSS SS. It's not rocket science -- you just have to read and follow the directions.
I appreciate your desire for robust gear, but that said: if you want to abuse the gear on your boat, go ahead. If you want to install it incorrectly, that's your call. If you want to use it to failure, be my guest. But I wouldn't be surprised if you were one day the victim of multiple, minor but progressive component failures that leads ultimately to catastrophy.
MaineSailor knows of what he speaks. The only thing I didn't see in his excellent post was the mention of use of Loctite thread locker on the second (outer) of the two lock screws. You shouldn't use it on the inner set screw because some of it might leak between the shaft and the collar making the collar very difficult to remove. That's another common mistake made by the inexperienced 18 year olds that work in boat yards (you know, the ones that flunked out of sub school). But, you'd know that, if you read the directions.
PS -- I spent a few years in the Navy, and IMO the 18 year old on a Navy submarine is a highly trained individual regardless of his rate.
PPS -- one of the things that I do to alert me to any movement of either the rubber compression collar and the SS ring-around-the-shaft is to make marks with a black magic market on the stern tube where the rubber compression collar meets the stern tube and where the SS ring-around-the-shaft meets the shaft. If either of these marks disappears then I know something is moving and needs attention. I have a look at these marks every day during my pre-start checks of the engine space.