I took the opportunity to extensively play with and test all three of the "high end" beacons (S1, Pulse, DPS) on the market recently when upgrading from a 10 year old tracker, and the Mammut was by far my favorite. To me, the interface was very easy and intuitive to read and use. The GUI has no frills or pictures of little buried men like the S1, which to me seemed clunky and awkward. Just a list of buried signals, a floating arrow, and a number; perfect. Marking signals is easy, and scrolling through signals in multiple burial situations is easy and gives you the info you need quickly to determine who to locate first.
Being able to hear the analog signal too also aids in searching, and if all else fails and the software starts going crazy, you can always switch over to analog mode and you're still in business.
The newer firmware has gotten rid of much of the annoying "Stand Still" and "Hold Level" messages that used to pop up all of the time. I rarely see any of these now.
As always for any beacon, practice with it and become proficient with it so it becomes second nature to use.
Bottom line; this is a great beacon with many advanced features that can really aid in a recovery situation. Even with all of the bells and whistles though, the interface makes it easy for anyone to just pick up and start using without prior experience. Worth the extra $$ over other models.