I've been bugging several people at CARS for years. There is no way they'll ever accept SFI 38.1.

But the good news is that the FIA is in the process of rewriting their standard. Once that's done, they should be able to accept almost any device which provides adequate protection.
So I'm holding out until then before I make my purchase.

BTW, there's a fantastic magazine article here.
It compares several devices, how easy they are to use, comfort, price, ease of getting in/out of the car, etc. It makes a point of NOT trying to compare safety. Since they are only comparing devices with some kind of approval, so they say each one has already been deemed 'safe'. So the purpose of the article is to find all the differences between each one.