I have had SPOT 1 since December 2008.
It has worked well for me in mountain environments, flatland environments, at high altitudes, and in extreme cold (-25F).
I read all of the negative reviews about it before I bought it, including Backpacking Light and the rants on this forum.
Like any product, some consumers want it to work perfectly under all condtions (e.g., inside a deep slot canyon) and want it for free.
IMHO, it is a good product at a decent price.
But, the rebate process was really bad.