I am like Justin. The first time I used my Onyx I was all the way home before I realized I still had it on.
I purchased mine at a local shop. I went in to look at them and the owner of the shop said he would match any other store. I told him what BPS was selling them for and he laughed a little and showed my the price sticker and it was $.99 less. I bought it and a replacement kit which is the cylinder and the little dohicky that sets it off when it gets wet. And one last thing - store them INSIDE where they will stay dry. Constant moisture will eventually dissolve the dohicky and you will find your PFD inflated when you go to get it out.