I have only Sigmas fro the same reason. money. I will admit that they are great lenses. I will tell you though, don't go by the magnification factor. If you need 300mm in 35, then get 300 in digital too. It will save you from wanting later. I have the Sigma 70-200 2.8 HSM and I will be honest it is a great bang for the $800, but I find myself wanting 400-500mm often when shooting nature. The 2x converter helps but cuts the 2.8 to 5.6 and that hurts. Overall, Sigma = great lenses Magick Michael