I learned to play classical guitar with a foot rest. I always hated it. I could not sit comfortably, balanced, or centered. My spine would hurt. I tried the suction cup brace for a while, but it would slide off or the suction cups would come off. Then you have to get the brace right where you want it again.
The sageworks uses magic to hold the brace right where you want it. Or is it magnets? Once it's set up it is locked in every time.
It admittedly does take longer to set up, which requires you to loosen the strings and command strip the inner magnet in place. But that is a easily worth it to me.
One change I would like to see is finger adjustable screws for the angle adjustments. I'm thinking something like PC Case Thumbscrews. The Thumbscrews sticking out instead of flush would need to be considered.
Needing an Allan key is make that adjustment is a minor inconvenience, but since I use this on multiple guitars with the addition magnet set it is sometimes needed.
Minor improvements aside, this is the best support that I have found on the market. I cannot speak to longevity or wear and tear on the guitar at this time, but I don't see that being an issue. If the cork pads wear out those can easily be replaced as can the command strip holding the inner magnet.