I've tested (not by choice!) my Point Two inflatable vest when bucked off recently and it was wonderful. Felt like landing on an airbed and didn't feel a thing. Expensive I know, but imo I'm worth it!
qr- alot of your choices are limited in sizes. Fine if you are a standard small medium or large but many people need a more bespoke fit. Racesafe would be my first choice but if you dont fit into a standard size i would go with rodney powell as they will make you one to fit. It is SO important to get the correct back length, etc and you shouldnt compromise because you want a specific brand.
A body protector is like a saddle - it must fit the user.
Go into the shop and without looking first at the price tag, then try it on and move about. If they have a saddle horse, then borrow a saddle and sit on it.
It should protect your spine from sacrum up and perhaps in the case of ladies your chest. But it must be comfortable otherwise you won't use it and when you fall off it will be hanging in the cupboard. I spent a lot of money on one and I confess, mea culpa, mea culpa, when I fell off yet again, I wasn't wearing it. I am an idiot.
It is the same decision as with the hat - does it carry the kite marks and does it fit AND WILL YOU WEAR IT! .
Then buy it.