I have just picked up one of these Canon 200mm IF 2.8 lenses at a good price after lusting after one for years. Anyone here use one that can share some of its good points and weak ones? How does it compare with the similar Nikkor 180 2.8 manual lens, considered one of the best made by Nikon? Also, I have the Canon 2x-B converter that I hear works quite well with this Canon lens, but might want to try the 1.4 converter and am uncertain which model is the correct one. I hear, however, two different thoughts about which Canon converter works on this 200mm lens. Some say the Canon 1.4x-A converter, designed for lenses 300mm or longer, will work perfectly. And Canon's own literature doesn't reflect that, because the lens was not manufactured until AFTER the literature for the converter was published. Is the Canon 1.4x-B (very rare) needed, or will the 1.4x-A work just fine? Anybody really know?