I love my HHR! I've had it just over two years and it has a little over 20,000 miles on it. I haven't had any major problems with it. I did have some brake squeak when it was new and that was fixed. I still get compliments on my HHR. Most people are surprised when they get in at how much room it has. Especially when I haul something in the back, they never think it will fit and it surprises them when it does! I get great gas mileage 30-33 on the highway and 25-30 in town, it just depends on how big a hurry I'm in! My Mom is considering an HHR for her next vehichle.
The exterior of the HHR, it reminds of an old woody and a miniature version of the old Chevy Panel wagon I also enjoy the remote start that came standard, the mp3 adapter and the heated leather seats!
I agree with everyone about the window controls...although I'm now quite used to them. I had some problems with blind spots too when I first bought my HHR, but have become accustomed to looking around them.