I was one of several testers for backpackinglight. We owned several, we used them extensively throughout the U.S. and Australia, and they did not reliably work.

In real-world testing, messages failed to get out a large percentage of the time. Keeping the unit oriented a specific way helped - but that orientation basically requires keeping the unit in your hand or strapping it to the top of a pack (or decking or thwart) - and even then, not all messages got through.

We also found the UI - that is, the buttons, labeling and LED signaling on the SPOT - potentially confusing (witness this week's story about the hiker accidentally pressing Help, then trying to recall the message, and the troubles SAR had getting information out of SPOT' shotline).

We did a report with extensive data and statistics to back it up - available to subscribers online - and our findings are consistent with those of many other professional organizations.

If it works for you and you're happy with it, enjoy. But don't belittle those who find SPOT a flawed implementation of what should be a really interesting new category - they're in the majority.