I have had mine for a little over a year. Use it sledding, camping, fishing, etc. I personally like it for the 911 button (that was the main reason purchasing it). You never know when and where, you may need help. I also have tracking on it, which is cool. The OK button is a nice feature, sends out an email with a google map link of where you are at. Most of my riding group has me put their wife's email addy in it when we are on our rides.
Overall, it is just another tool. You still need a GPS. I also carry a FRS radio, and cell phone. Try to have all my communications covered.
Quick little story, that may help sway your decision. Borroed out my SPOT last year to a co-worker. He was going on a 4 day winter camping excursion in the Boundary Waters (northern MN, very remote). Him and his buddies were on day three of their trip, when out of the blue two people came walking up to them (out of breath and in a panic). My co-workers group were 4 portages into the BWCA (this is a very good hike, most people only go in two portages in the summer when conditions are good). They had no cell service where they were at. These two guys were in a party of 6, and they were one portage back (from my co-workers group), when one guy went down (having a heart attack). They sent two guys to follow tracks (thats how they found my co-workers group), and two guys north (Forest station just on the obrder of Canada) to try and get help, and left one guy back with the guy that needed help. The first words out of there mouth (before even saying hello) were, "is anyone a doctor or have medical experience". Unfortunately my co-workers group could not help in the situation with medical experience, but my co-worker handed the SPOT over to these guys and said go back to your downed man, and press the 911 button. They took it, and went back. My co-worker figured he would never see the unit back, or ever see these guys again, and have no clue what had truly happened after this point. But, they saw these guys on their way out of the BWCA, and got the SPOT back. So, the question was asked, "how did it work out"? These guys went back, and were hesitant on pushing the 911 button (ultimately never pushed it), S&R did show up at about 4:30 PM (the guy went down at around 10AM in the morn). The two guys that went north ran in a forest service worker, and relayed the message, forest service called S&R. S&R was deployed around noon time frame, finally found them at 4:30PM. Once S&R was there, the guy that took the SPOT, said "should we have pushed this button?". S&R looked at him dumbfoundly, and said we would have been here 3 to 4 hours earlier with a helicopter vs. here now (4 hours later) calling for a helicopter. They did airlift the guy out, and he did survive, but he could have been to medical attention much faster with the use of SPOT vs. a general location for S&R to look for the party.
I always carry my SPOT with me.