Despite Sony's "official" statement that their BDP-S1 standalone Blu-Ray player only uses similar parts to the Pioneer BDP-HD1, there's been more than a few similarities noted in their reviews. The Pioneer and the Sony players all have the same format support, menus, disc drives, back panels, and load times. Now, with the release of The Descent they crash and burn in exactly the same way.
Reason? Both players don't support BD-J (Java enhanced discs), which is what Lionsgate produced The Descent in. Gee, if people are having a hard time telling DVDs from Blu-Ray and HD DVDs, how do you think they'll react when you tell them their player won't support BD-J discs? The PS3 plays back these discs just fine, and Sony's said they will release a firmware update to upgrade to BD-J support "sometime early this year".
Update: A Pioneer spokesman says they do support BD-J, as evidenced by The League of Extraordinary Gentlemen working fine. It's just something odd with this batch of The Descent titles. Maybe it's a tech somewhere along the line sparing you from watching the movie?