I tried it again this morning.
Yesterday my mileage was 11.44 and today it was 11.37.
For me, that's close enough and depending on how much bobbing and weaving i do it could be spot on.
I can't really say if it's more or less accurate than my cyclometer but I never do fully trust those things because it relies on YOU to input the correct tire circumference. There just too much room for error there for it to be accurate. Even varying air pressure can make a difference in rolling circumference. I trust gps a lot more. I need to get ahold of a small gps that I can use to compare with trailguru.
One thing I did notice that was quite different between the two days was Max Elevation and both Total Ascent/Total Descent. Min Elevation was the exact same.