I would give it a go for sure, I have back and neck issues and have tried so many things to help. I actually have a compression posture shirt and you can tell the difference when wearing it pulls the shoulder back and keeps them there and it does help. It does take some getting use to though. I even wear it for work as it helps with slouching at the computer screen.
I feel like to try it out, I'd have to have one of those problems. My posture could be improved I suppose. However, my back pain went away when I spent a decent chunk of change on an ergonomic office chair.
It would depend on how it looked and felt. I have clothes I have paid that much for so it wouldn't be that much of a stretch. I do try not to wear my pants that were expensive on the golf course as they get dirty but if they made me feel and play better I would consider it.
I think I would try something like this as described in the OP, but I guess I would have to see it, learn more and maybe have a money back guarantee. Even then, I am not positive I would jump on board. For example, I think Squairz shoes would be great for my feet; they have money back guarantee but the fact that I can't try them on and some of the claims seem too good to be true has had me not pull the trigger. Same kind of thing with the Stamina Pro patches; I have been so close to buying many times and never quite done so.
The lawyer side of me has to make clear that “FDA registered” is a meaningless, misleading term that is often used to confuse consumers. The FDA being aware of either the product or, more than likely, the facility does not mean that it has any approval or proven science behind it.
That said, the idea sounds interesting and worth a tire kick.
My biggest concern would be durability. How long will it last? I'll buy it, but if I'm constantly wearing it and it only last a couple months, it's a no. If I can get a couple years out of it, I'll take three.