They're both 'useful' (the latter one less so, since it deals primarily in lenses that aren't widely used) to some degree. I find informal real-world results/tests, even with a variety of subjects and film stocks, etc. to be more useful to me - they're more representative of what I might conceivably shoot. I guess I'd say my interest in reading lens info has more to do with finding out what kind of imaging characteristics I can expect in average usage, rather than an objective finding.
(Sadly, neither test focuses on lenses I might conceivably buy in the next six months - 50mm Summicron v. ZM Planar vs. Nokton...)