I am looking to buy a telephone lens mostly for portrait work have narrowed the field down to Tamron and canon. Read somewhere that the canon 55-200 was not up to much and that the Tamron one much better?
I like a nice fast aperture when I shoot portraits - f2.8 or faster - the two lenses you're looking at are budget telephoto zooms. Great for beginners and people on tight budgets but portraits? There are better alternatives out there I reckon.