It works OK.  There were a few glitches last year they have been working on and think they have solved.  It isn't perfect and I don;t think will replace a physical gauge if you want perfection, but it is close enough for my needs.

Is it worth it?  Don't know.  Haven't paid for it.  Got 3 locations last year through a seed company promo.  Was at a meeting over the winter and won 10 sites this year. But I can tell you what it rained at Mom's, Grandpa's, Great-Grandpa's old farm 150 miles away, and various fields.