So anyway I ran the test on a bunch of playback devices and I can say the 360 should score 40. You know those tests with the scrolling texts? There's no way it should look as bad as it did in the extremetech tests, giving it 20 points right there. Maybe the difference comes from my 37 inch vs. their 59 inch. According to the HQV tests, the 360, xbox 1, and my $50-60 DVD player are pretty equal (scores 35-40) while my HTPCs score 100+, which is consistent with what I've seen online. Interestingly, the XBMC sucks for DVD playback (which is why I said it was unwatchable) but using another player like the dongleless one was much better and scored similarly to my stand-alone and the 360.
The 360 choked once during the test (which is just DVD playback lol) though. Still, it's not as bad as the article claims it is. They're a bit guilty of sensationalism. It's good enough for most of us, and videophiles will have their Denons or cheaper HTPCs. They probably could improve it though, given the 360's horsepower.