From the bottom up.
Toshiba HD - discontinued format and I have about 40 discs that can only play on this player.
Sony 4k- also plays DVD A and Sacd, but not Dolby Vision.
Lg 4k - can play Dolby Vision and Hdr
Yamaha- plays DVD A and Sacd
Oppo- region free and analog DVD and Sacd
Thats my main 5-- a little overkill, but I use them all.
Sony 4k in the bedroom and Panasonic Blu ray in my den makes 7.
Good job on the HD-DVD player. Good stuff, stabbed in the back by the back room deals of Sony