Nope, it doesn't work well in the forest. They actually tell you that on the findmespot website if you read between the lines. They say, "clear view of the sky", which translates into, "doesn't work in buildings, caves, under heavy forest canopy, or in steep-sided canyons." The problem is that it uses microwaves to communicate with the satellites. Microwaves are quickly absorbed by most materials (hence microwave ovens), so you have to be able to see the sky - the more sky the better. I would bet that SPOT also has trouble in extremely wet weather because of this (like DirecTV reception - Rain=Freezing/Snow). Essentially you take all the problems that GPS devices have obtaining a fix, then compound them with the problems that satellite phones have with maintaining a connection and you have all the problems that SPOT faces.

The more I hear and read about this unit, the more I'm convinced that it is primarily a fair weather tracker/messager. The emergency feature isn't reliable enough to sell the unit on that ability alone.

If you plan to buy it as a "peace of mind" device for your loved ones it's probably worth the expense. If you plan to buy it primarily as a "save my butt" device - get a real PLB instead. I'm going to wait until SPOT II (or whatever they're going to call it) comes out with all the features that should have been on this unit (two-way messaging, message confirmation, real PLB).