It depends on the taxon. Most of the newer taxa have pretty good
information there, but some others don't. Also, the information provided
for newer taxa is usually based on the describers' opinions, which sometimes
isn't the consensus view. Information for older taxa is usually sparse, or
based on a particular study (like how Archaeopteryx's centers on its
nomenclature). And it hasn't been updated since 2002, so it's a bit out of
date. But it's not like there's a better resource online yet. My bird
section's certainly not complete, for instance.