Sergio
I went with the inreach explorer. Sorry to spot users for the list below.....
There are some heavy hitters that steered me to it:
1. The inReach has full global coverage, Spot does not. When you have a potential blind spot when using a gps locator (as you do with the spot system) it renders it useless if you land in the wrong place. This holds true for Scotland as well as exotic places.
2. Two way messaging. Your phone is useless if it doesn’t have a signal or the battery runs out, or gets cold and shuts down.
The other point I heard someone say is “I’ll get one when I do XC”. My opinion is that If you are out on your own and doing a top to bottom - you should have one. If you are lying with a broken leg or worse - it doesn’t really matter if the car is 50km or 50m away - you need help!
An inReach and a buddy system will keep you covered. Anything else has holes.
Why the explorer? It had a feature or two that I thought would be useful. Plenty of comparison reviews if you want to have a look. I don’t remember what they were......
As for contract - I went with basic and will pay the rest as I use it for messages and tracking. You can go month by month if you choose, but spread over the year I thought it would be six or two threes for total cost and it saves having to remember to switch on / off service.
Personally I also now fly with a flymaster live for further safety / coverage. There are also phone apps that can do a similar job such as followmee. It will likely mean you have to fly with a battery to keep the phone charged.
Cheers