Appears to work quite well, gives consistent readings.  The trick as others have mentioned is lifting it up SMOOTHLY.  A jerky lifting motion will give sporadic readings.  Also it is more "robust" than I had imagined.  It's definitely a bit bigger/heftier than it looks in the pictures, especially the strap portion.  What I like most about it is that it's compact/light and easily packable so I can bring it with me for the return flight home.