Oppo was offering an upgrade from the standard 83 to the SE, if you bought your player before November 9th; the offered expired at the end of the year. It was basically to allow people who got the 83 before they knew there would be SE model. Now it can only be bought outright.
But why would you? Yeah, Oppo put some nice DACs in the thing, but it's bass management is slightly flawed (fixed at 100 Hz for any speaker set to small), and has no individual time alignment for speakers. Just a generic lip-sync which affects all channels equally (well not the extra, high quality stereo pair, they don't get any delay applied at all).
The best I can tell, the SE is for people who listen to multi-channel music through 5 or 7 identical full-range speakers, and use an analog pre-amp.
Since it offers no improvements on the digital side, and a receiver with HDMI connection is much more flexible for normal speaker configurations; all anyone would really need is the BDP-83, or the 80, if they were not viewing many DVDs anymore, and mostly watching BDs.
