Well, I got my 1610 yesterday. I have to say, this UI sucks and there are much fewer picture controls than my Pioneer 51. Right now, I definitely prefer my Pioneer. However, this player is faster and the disc tray open/close is much quieter. Right away, I updated from 1.006 to 1.008. NO SD CARD NEEDED. I never put one in the player. So, the main reason I got this player is that it has Source Direct, since I have a VP. I moved my Pioneer in the bedroom cause I have a 2 channel analog setup in there and the Pioneer has awesome analog audio. I'm glad to report the Denon plays PAL just fine. However, I wish it were SD DVD region free, like my Pioneer is (remote hack). I didn't even bother with upconversion, since I use Source Direct to my DVDO Edge. That's why I got the 1610 over the 2010. Oh, and the "Pure Direct" mode is neat, you can turn off the front player display or you video section all together. I just turn the front display off.
To check firmware - 1,2,3,4,display - somewhat quickly. Read that in the 2010 thread...
All in all, it's a nice player. I do prefer my Pioneer 51 over it, but for the price I got it, I am happy. It's nice to have matching AVR and BD player now.

I would tell people to get the Pioneer 320 over this player, unless they just wanted a Denon. The Pioneer 320 and Pioneer 51 are very similar and I much prefer my Pioneer. The Pioneer should have better upconversion, 7.1 analog, more picture controls, possibly region free SD DVD with remote hack (Pioneer 05/51 can be) and much better GUI. However, the Denon is quicker (not a whole lot), much quieter disc tray open/close and easier to update firmware via ethernet.
Denon - PLEASE add some more disc info to the Display screen! Wow...
Edit: I noticed on the box it said "DTS-MA Essential". I think the Pioneer players have this too, but I can't be 100%. You should really research it, but I think it means it won't internally decode DTS-ES or something. I can't remember, I bitstream anyway.