hey people. stuck between a couple of lenses. a nikon 55-200mm or a sigma 70-300 mm. I feel like I would really like the extra zoom but I also feel like the nikon would be a better quality lens...has VR...is a Nikon...so is my camera, all that stuff. Don't want to fall for a gimmick. Could someone show me maybe with photos what the extra 100mm does. I'd really appreciate it! Also maybe some feedback from owners of these lenses would help.