I have used Spotwalla mostly and will probably continue to do so, although I may also investigate Spot's journey method as a back up!
Briefly I investigated bubbler on the phone but as one needs a phone signal that doesn't work for me!
My main reason for using Spot/Spotwalla was to enable my wife to follow my journey wherever I may be and so she knew I could get help should the worst happen.... I did have an accident in 2012 that could have ended quite badly had someone not stopped to help.... no phone signal, isolated area, very cold.... off on ice resulting in me being off the road and down a bank..... and so on..... they say any accident you walk away from is a "good" one, this was one I physically couldn't walk away from, but I could crawl....