I dont know the difference because I never used Polar Steps but I have been playing with FindPenguins for couple of years and needless to say The Camino was absolutely a part of it (and like
@trecile said - I plugged it into the Forum proper so other folks can follow the journey)
Here is what I like in a nutshell
It does not cost you (or anyone else) anything to join.
You set up a 'new trip' at any given time you wish and all you have to do is simply 'activate' it on the start day and the app will start the tracking (if you know the end day and plug it in - then it will stop at the end of that day as well)
You are allowed UNLIMITED footprints (and heck you can create a new footprint exactly at the same spot than the previous one - works like a charmer if you have lots of pictures you took - something like Burgos Cathedral comes to mind.... I think I came out with 3 footprints).
You are allowed 10 photos and 1 video per footprint (but then see above so...)
the Upgraded account allows you to do 20 photos and 2 videos per footprint.
If you anticipate lots of traveling and see a merit in it - you can grab the annual upgraded membership for a nominal discount, else you can pay on a monthly basis pay-as-you-go starting from the day you upgraded (thats what I did - kept it for 2 months while on Camino)
you can immediately take a photo on a footprint or you can take them with phone camera and then attach later on to a given footprint (just keep track of what you are doing it can get a bit "much")
I would take a combo if immediate footprint photos and photos to attach later on (still need to at least create a footprint for that spot) and then work though all the 'editing', putting my comments and stuff in the evening in the albergue with a good WiFi available and upload (if you read the site on how to use it - you'll see what I am talking about)
The great thing is that the app continues to track you even in Airplane mode so you are not running battery down. (I would also caution that if begins to track you and stops from the place you activated or terminated - so... i usually do NOT activate until i am in the airport... else it will nicely pint to your front door and i am sure you dont want the whole world to know that nobodys home when you are travelling)
Take it out for a trial run - just pick some random 'trip' could be one of your training walks and play to get an idea of how it works.
I totally love it and it was an awesome way to keep family and friends in the loop and I enjoyed the interactions (folks can leave a comment on footprints - again dont even have to be members)
BTW - if they do sign up themselves then they can request from you a permission to follow you. if they do - they will get a notification any time you upload\post something new.
Good luck and Buen Camino!
P.S. Arent you a little late planning a Camino 2020?