I own a Canon XSi and looking for a zoom lens. I was reading reviews on tamron and sigma 70-200 f2.8 on dpreview and for both the reviewer says these lenses are not ideal match for the Rebel series. Is this a real problem? does anyone here own either of these lenses with a rebel?

if these are a problem, can someone recommend a fast zoom lens with good image quality?

tia

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