The Interweb purchase experience will vary from new to pre-loved I expect.
I did a new purchase through carwow and had the registered dealers send quotes etc, found a good price, spoke to a salesperson who was actually very helpful. The car was delivered and all was well, then again it was new. And it all went pear shaped following due to the car but that's a different issue.
I would be more nervous if it was pre-owned/not still covered by the vendor warranty.
I may allegedly know someone who took one of these companies up on the "14 days or your moneyback" to save money on a car rental for his weeks UK holiday. At the end he said his missus hated the colour and it broke down.
