excellent question, & closer than it first appears...
sims has better pedigree & more auspicious rookie season...
HOWEVER, henderson also has good pedigree (before hurting his back he looked like one of best defensive players in nation as maryland sophomore, picked early in round two, few picks after barnett, as first LBs taken in their draft), and is coming off his best season...
right now i'm guessing in a lot of situations you couldn't get sims for henderson...
when i looked at a few big play-driven scoring systems i play in, i was surprised to see henderson at #7 & sims at #16... in another, it was #8 & #14, respectively...
if this scoring disparity continues, obviously henderson's value relative to sims will surge...
in dynasty leagues, henderson does have back history, but that is mitigated by sims concussion history...
henderson was re-upped to a contract extension in '06, i think...
before looking at their season-ending totals, i would have thought sims, no brainer (especially after such a promising rookie season)... in actuality, VERY CLOSE... again, given jene's sensible qualifier, contingent on scoring system...
i do think sims is more talented, but henderson is in a great scheme... i do think sims has a chance to be a special, near derrick brooks-like talent, but that is far from certain he will actualize it... if i already had a solid roster, & could afford to take the risk, i might prioritize sims...