Product review (5 stars): Excellent Product - CUSTOMER SERVICE EVEN BETTER!
To be honest, I'd give the product 4.5 stars - it's the customer service that brings it to an overall 5 for me.

They sent it to me promptly.  It worked great for three months, then one day went completely dead for some reason.  I contacted the seller, even though it was months outside of the return window.  They authorized the return anyway, so I sent it back to them to take a look at.

After they got it, I called and they told me they couldn't find a problem, it seemed to work fine.  I could hear it beeping over the phone as they told me, so I figured okay, that's weird, but if it works, great, go ahead and send it back.  They did.

I got it back.  It worked great for about five minutes, then died again.  Evidently it wanted to act like one of those obnoxious electronic defects that never wants to show itself when the repair guy is looking - it happens from time to time, even with otherwise excellent products - nothing is perfect 100% of the time, so no worries .

I called them again and told them what happened.  Without any resistance at all, they told me they would send me a replacement.  They told me not to spend the money shipping the old unit back again, just to provide the serial number so they can contact the manufacturer, and they would pay the freight on the replacement.  It arrived a couple days later from Florida (I'm in Seattle).

The new one is working great, and this seller does not hesitate to correct a customer service issue with the utmost integrity.  Five stars all the way. . .  seller is a credit to the Amazon community.