The Tamron declined because color reproduction and detail the Nikon lens failed subjectively better. In addition, the mechanical switch from macro in the "normal" mode is a bit fiddly (only works in a certain zoom range and earlier needs to be switched to manual focus. Although not a big problem, but annoying if it has to happen quickly, or should. Tested was the way with a D3100! Significantly better (especially in the upper zoom range!) be photos with the Nikon lens due to the integrated Verwacklungsschutzes. A clear advantage if you just want to snap out of his hand and is not always a tripod with or only to be set up. All in one for just over 30 more for the Nikon lens has for me / us the Tamron unfortunately lose out ...
(Imho better) Age Naive here:
Nikon AF-S DX Zoom Nikkor 55-200mm 1: 4-5.6 G IF-ED VR lens (image bar.) Incl HB-37 (52mm filter thread).