I've put over 7000 miles on mine since mid-July and no problems with mine other than the idiot behind the wheel for the first couple of thousand miles (until I found GH that is). I just managed to recover from those first 7 tanks of stupidity and made hypermiler status just today.
I'm pretty proud that I was able to manage that under less than ideal (somewhat hilly) conditions on my commute here in CT. I can't be happier with mine so far!