El Gringo.
Tamron 18-250 mm har fått betydelig bedre omtale enn Tamron 18-200 mm, se f.eks. http://www.photozone.de/Reviews/Canon%20EOS%20Lens%20Tests/45-canon-eos-aps-c/293-tamron-af-18-250mm-f35-63-di-ii-ld-aspherical-if-macro-canon-lens-test-report--review