I am not aware of any advantage of buying via a dealer.
In any case, most used piston GA dealer sales are gone on a broker/commission only; the dealer has prob99 never seen the aircraft, and he just gets a slice of the proceeds, in return for running ads in various mags, websites, etc.
No solicitors are involved unless you are doing more complicated stuff, or you are selling to somebody obnoxious and you don't want to deal with him directly
The prebuy check is vital.
What are you buying?