^Chris, the 4311 was a benchmark trendsetter model in many ways. The flagship prepro and AVR owners had to get a $1K upgrade to MultEQXT32 to even keep up! I recommend you not consider any model without XT32. Most owners including myself are still enjoying theirs immensely. It is a reliable, high-value model. Just recently I reexamined some upgrade options and none are compelling.
New models within the Denon line that are obvious alternative choices are the under $1K X4000 and the almost $2K 4520 (street pricing from the most competitive authorized dealers). You should call jd at AVS to discuss what features are important to you and to decide on the right model-and you'll get a great price! Oh, BTW there is also a promotion going on right now: the 4520 packaged with the 3313 Denon univ BRP. jd's contact info is in his sig just a few posts up:
I've not heard of Darbee in an AVR as yet. I've no idea as to the prospects of it being included but wouldn't hold out for it. Personally I've considered a darblet but haven't seen the effect myself. It sounds like a small, preference video enhancement that many folks who are discriminating videophiles like. Oh, BTW, if you're in the market for a nice universal BRP there is a brand new Oppo 103D upgrade model (D for Darbee processing) for $600 ($100more than the std 103).