What to buy is going to dictate where to buy in many cases. With Tone Poet, I had no problem buying many copies of things like Katanga! when it was in print. (why so many- I give ’em away). Records like that I have no problem with Amazon.
Rare records: it’s nice when the trusted seller lines up with the record you want. That happens sometimes.
I don’t buy that many new audiophile records, and at a certain point, I stop buying the latest greatest reissue of something I might already have multiple copies of.
I buy a fair amount on line, and many of the sellers of private label jazz are not big businesses. My best advice for any record of value (and this held true across genres and countries where the copy was located) was to have a dialog with the seller about the history of the record, its actual playing condition (whether you want them to play test is another question) and your right to return.
I don’t like wasting anybody’s time, least my own. But I’ve gotten records from the MidEast and all parts of the world- records that in 2006-7 were in actual mint condition, including paper ephemera, in around the $100 plus price range. Today, those records command a multiple if found and condition is a key issue.
I’ve slowed down. Some records still come in. But with grading and pricing inflation, my "want list" is pretty short. And I’ll listen to anything, at least once. (Sometimes, it takes more than one time through to "get it" aside from the benefit of playing through a cleaned copy for the first time just as a QC/nit check step).