I have a friend who used to. I didn't really get his fascination with it. There are so many places that will get cell phone reception these days, I tend to prefer to not be in contact.
The SPOT device is pretty cool though, especially with the new stuff they have for it. You can sync the new SPOT Communicators up with your smart phone (iPhone and Android so far) and send actual text messages out instead of the two or three pre-programmed messages you could send with the other models. You can also do that with the DeLorme PN-60w GPS/SPOT combo.
I carry the old model that can only be pre-programmed, but it's nice that I can send my wife messages about how I'm doing without having to actually hear her complain about how dangerous hiking/climbing/backpacking is...
