For the price it's a very decent performer, if you can get stable shots without IS depends entirely on the conditions and your grip. It's a FF designed lens so with an APS-C your looking through the better middle part resulting in decent sharpness, little distortion, CA, uggo Bokeh though. Go to a local shop and try it out, is the 70-200 L better? Yes.
Is it worth the extra cash? That's something only you can decide. I'd go for the L if you can, and not only because it's sexy and white, it's the better lens.
lcoopmanI have the tamron 70-300 and its a great sharp lens. I don't regret buying it at all. Would highly recommend itb
It's about as sharp as my thumb when it tries to cut onions. For it's price: good, in relative terms: nothing remarkable.
Professional narcissistic asshole, always right, never wrong.
Shoots tri-X and draws monochrome studies of models @ http://www.omnidata.fr/