I've always bought privately, but taken someone else with me where possible who could be a bit more objective.
All were identified through Miscellany, and although I had looked at dealers but couldn't find what I wanted, I was actually happier to buy privately and save a bit of money. In each case, the sellers were genuine 'men of their word'.
I don't expect to buy another, but if I were to do so I wouldn't have any problem buying out of Miscellany.
Malcolm T