If I want to have my 70-300mm attached to my XT body in bag and carry two other lenses and a bulky adaptor. The price difference is $17 but the 300 looks so massive yet the 200 looks like it might be too small.. I like this bag because of the rain cover it features I have been out in the rain (not on purpose it just happened) twice with my little Cirrus 140 and as soon as I get back to the car I have to dump everything out incase it seeps through. I only have $100 or under to spend so I am limited really in what I am looking at. 300 http://www.the-digital-picture.com/Reviews/Lowepro-Slingshot-300-AW-Review.aspx 200 http://www.the-digital-picture.com/Reviews/Lowepro-Slingshot-200-AW-Review.aspx Thanks for any help..