I got an 820 recently and very happy with it (using it with a 48" LG) , but given the quality of some of the 4k discs coming out, Im very disappointed (GoT 1-8 box set especially disappointing for a premium set - quality of individual discs is plain awful) there are others that were seemingly released for the sake of it without putting much care into the production.
Ive been a BR collector since the PS3 came out, and been collecting 4k for about 14 months (and have about 150 in total) - but UK has been absolutely killed for imports since Brexit, those discs that were $25 for a recent release are just too expensive now with postage and customs charges - at least 1/2 my collection is imports because I like getting them early (unless its only a week or so difference in release dates)
I really hope the BR and 4k disc market survives, Ive just got a horrible feeling its going to struggle badly - I know the DVD market is still pretty healthy but there just isn't any growth in the generations above this
Oppo has disappeared as a manufacturer along while ago - I believe the only premium brand /model is the Panasonic 9000 , otherwise its relatively budget players.