I would think that the AFS 70-200mm f2.8 would be better in low light than the 135mm f2. There is only one stop between the two and because of VR I would expect the zoom would allow you two stops of lower ISO or two stops of lower shutter speed. Framing with the zoom is also a plus. It certainly focuses fast enough. I have also had very good luck with Nikon's AFS TC's. I guess the down side would be the zooms bigger size and weight for both traveling and carrying. The zoom is just about twice the weight.