As a Nikon shooter, I've had my eye on the Tamron 24-70mm f2.8 VC, but I've been hoping to find an in-depth evaluation of its image stabilization. That is one of the aspects of lens design where you can see tangible performance differences between third party and OEM lenses. Tamron VC zooms have had a reputation for slow-engaging image stabilization that can actually blur a photo that's shot too quickly. The 24-70mm f2.8 is far more expensive, however, and Tamron may have improved its image stabilization performance.

Among Nikkor zooms, the closest image-stabilized competitor to the Tamron would be the full-frame Nikon 24-120mm f4. I've used this lens on the APS-C D5100, which sharpens up its relatively soft corners. The 24-120mm is about the same price as the Tamron, and probably performs similarly at f4. The 1.5x crop of APS-C has narrower depth-of-field than MFT, and in low light I actually prefer to shoot image stabilized as low as 1/8-sec shutter on f4. There are situations, however, where f2.8 would be awfully helpful, though the 120mm zoom range is a big advantage for the Nikon.

I've also shot image stabilized video with the Nikon 24-120mm and it's very smooth. If the Tamron's VC turns out to work reliably for video as well, I'd probably go for it.