No comparison. Canon. Ooops, sorry, wasn't one of the choices. But, look in mags, Canon has discontinued the 28-70 2.8 and 70-200 2.8 and they can be had fairly cheap (I've seen the 70-200 as low as $850), I've also seen the 17-40 4.0 as low as $600.
Canon EOS3, 75-300mm IS
E. Foltz