Notwithstanding the valuation, a number of observations would spring to mind:
1. Would seek the opinions of others, but their website is very good as are their descriptions, are they significantly better than Dealers websites. IMHO, no they are not and the pictures / descriptions would not be enough to make me buy the car.
2. The descriptions are only as good as the the person who uploads the details, mentioning a car has memory seats and it doesn't or vice versa, when the customer hasn't seen the car will heavily impact on sales and returns.
3. Nobody really knows what the return % will be, if you get 10% or more you are in the brown smelly stuff.
4. Do they hold the P/X for 7 days, if they do, that's a lot of dead money?
5. 31% of people don't trust the local Dealer, 69% therefore do and how many of the 31% will trust someone selling a car they can't touch?
@Bmx Bandits very valid point on manufacturers proactively disposing of their vehicles, not sure I will see it in my lifetime?