I have a VERY old eTrex Vista that I use for backpacking in the Cascades, but it does not get a reliable signal unless I'm in the clear. I've borrowed a friends 60CSx and it was much, much better. Some of my hiking is off the trail so now I'm looking into a PN40 because it has the ability to overlay contours on a satellite image, which is exactly what I need. If you're sticking to trails then the 60CSx will do just fine.
I also have a SPOT (used all last year) and the tracking is not worth it. I've always been able to get an OK message through but I just set it on the ground (clear above it) facing the sky while taking a break or making camp. Never had to use the 911 feature, but from my experience you'd better have a good view of the sky, or be able to crawl to it. The problem with SPOT reception, from what I've been able to determine, is that they use the same antenna for the GPS and for sending messages up to the satellites.
