As an owner of two OPPO players I love, and as someone who hates to give Sony any of my money, I must add that the UBP-X800 4K player I bought in 2017 ($159) is the best non-OPPO player I've ever used. Picture quality, audio options, snappy transport, simple remote and just well behaved all-around. Won't play my burned DVD-As (not its mission) but does play burned BD (AVCHD)! Shocking that it's a Sony product (playing actual DVD-A discs on it makes me gleeful with irony).
Probably won't make a move on one of these (Sonic Wiz maintain mode) but curious to see how it plays out. Given the top dollar (aka insane) prices the 4K Oppo players command, it's only logical someone would try to pick up the mantle.