http://www.photozone.de/canon-eos/190-canon-ef-28-135mm-f35-56-usm-is-test-report--review
Photozone seem to like it, not stellar but nothing bad to say either. My only concern would be that as a walk about on a crop sesnor SLR it's not very wide which I would find a bit of a limitation allthough you may not mind.