I love my Keurig! I bought mine at Costco last Thanksgiving, it's a model B77. Use it *all* the time.
Unfortunately, I just started having some trouble with it. The water pump was sometimes not working well, and I'd have to turn it off and on and mess with the water reservoir to get it to run. I called Keurig about this yesterday morning when it wouldn't make my morning cup. They're sending me a new machine, no charge to replace it.
I had heard that there were a batch of them that had this trouble with the pump, and I couldn't be happier with Keurig's customer service response to the problem.
Where else can you buy an electric appliance that you use daily for 7 months and then get a full, no hassle replacement when you have a little trouble?