Backcountry safety and PLBs

Since almost all my tramping is in backcountry about as remote as you can get in the North Island, and solo, safety is my first priority. I am prudent, perhaps cautious, and am well prepared. However, the stress of those close to me when am in the mountains detracts a little from the experience. I had looked at getting a personal locator beacon (PLB). The first choice is GPS enabled or not. PLBs with a GPS onboard are more expensive but can send your exact (if you can get a gps signal) location with your distress call. The newer 406MHz beacons also send unique information that identifies the unit sending the signal and contact details of the owner, perhaps helping with the search. A good deal of my tramping is river routes often with steep sides. My Garmin map60 struggles, often with one or two satellites only. In this situation, would a GPS enabled PLB get help to me any faster than one without? Where you can get a GPS fix, this feature can get help almost straight to you. Having decided to spend the $$$s on a GPS PLB, I came across the SPOT messenger and it has added a whole new option. The Spot messenger (google findmespot) has an onboard GPS and can send a distress signal but also has some other, very useful, functions. The first thing that caught my attention was the ability to send an 'I'm OK' signal with your current location. This goes to a phone as a SMS and/or email as a Google Maps link. Awesome! Now I can let them know where I am and that I am fine. Everyone's happy. It can also send a 'Help me' message for non life threatening emergencies as well as a "911 request" for a full blown emergency. All messages have your current location (if you can get a gps fix). This additional functionality comes with using a commercial satellite system and therefore there is a yearly subscription cost at around USD$100 with some more functions available at a further cost. This means that the signal will be detected in the US not in NZ although it will be passed on immediately, it does add another 'cog in the wheel' and a place for failure. Forums in the US are full of problems with getting a signal although New Zealand and Australia apparently have very good, strong signal coverage. I have been unable to find very much feedback on this product in used in NZ. Anyone have a comment? Sorry for the longgg post :-(