Originally Posted by
NeilGunton
The thing about the SPOT is that the status messages it sends are one way. It doesn't get any acknowledgment that the message was actually received by the system, so it's possible for updates to get lost without you knowing. Same goes for the rescue "save me" function. This, to me, is a fundamental flaw in that system. If you want to spend a bit more, then there's the DeLorme InReach SE, which utilizes the Iridium satellite network (like satellite phones), and has two way messaging. This means you can know when your status updates have gone through.
As with all devices like this, it's not perfect - but you have to scan through the reviews and try to decide for yourself what criticisms are valid and applicable to your use case.
Amazon.com: DeLorme AG-009871-201 inReach SE: GPS & Navigation
I've used a SPOT for four canoe trips in northern Minnesota and Canada, more in the middle of nowhere than I could get on a bike. It has performed flawlessly. I suppose it's theoretically possible for updates to get lost, but it's never actually happened to me or anyone I know.