Since many DVDs only have a two channel sound it is a good idea to also make a two channel connection to the reciever, along with the digital six channel to the decoder, so you can enjoy the added benifits of ProLogic surround sound on two channel disks. Here most DVD players are pretty much the same. They may call the features by slightly different names but the features are written into the standard. All will have parental control. All will have mutilple sound tracks.
All players have mutilple angles and subtitles.
One difference I have personally come across is some players allow you to bookmark a section of the DVD and return to it later. Flip a coin for this one. Personally, I like the direct time input. The only real new advance on the horizon is the DVD changer. With this player several discs can be loaded and selected at the same time.