Here is the one I am leaning towards:
http://www.staples.com/sbd/img/rebates/pdfs/728522.pdf
but I can not find anything about Optical Density and dynamic range, of course I could be overlooking it too.

I really like the duplexing b/c with my DH's business we do a lot of two sided printing.

I could go with this HP: http://www.staples.com/sbd/img/rebates/pdfs/703473.pdf but I had heard that Canon and Epson were better and no Epsons are available here that do what I want. This one would give me some $ left over...hehe