[Giller]

I really think you could flip a coin, dealership vs. private sale. Private sale you at least get to talk to the previous owner and get a read on how well he maintained the car.....with a dealer - they do have a reputation to maintain so for the most part (always exceptions) they will do their best to sell you a good car. Poor reviews can ruin a business.
On the flip side - the private sale dude could be lying through his teeth and once you've bought it, you have no were to go if he did.
The dealer - he's out to make money, so yes, you might pay a bit more.

There's no right or wrong - find a car you like, get a thorough PPI, find out all you can of the history and go from there.