I prepaid for a 4 star hotel through Kayak only to find out when I showed up at the hotel that Kayak never confirmed my reservation and I had nowhere to stay! You can imagine the shock I was in and it was a busy convention week so I did not have many options. I ended up scrambling into a miserable other hotel that was half the price of what I paid for and they would not refund the difference of what I prepaid to Kayak. A terrible and unforgettable experience and Kayak has done nothing to make it right.