A few more tests done indoors.
The Nikon does appear brighter, but my previous post seems bit optimistic, perhaps there was a change in ambient light. But half a stop is true.
The focal length is less of a difference with objects that are further away (5m and up) (, just like you said Derrel)
the VR on the Nikon works better then the VC on the Tamron, Nikon claims 4.5stops, I can say this feels true.
The Tamron feels more like 3stops only. So for travelling, the Nikon is the clear winner overall.
The handling of the Tamron is less of an issue than expected (like you said, ac12), it kind of feels nice and more balanced.
sharpness is overall similar, perhaps a bit less on the tamron at f4 compared to the Nikon wide open.
the bokeh on the Tamron is softer and better than the Nikon, of course because of the f/4. When you put the Tamron 210mm f/4 VS nikon 300mm F/5.6, the Tamron still has more DoF and nicer results.
The Tamron indoors and with flash, for events and people, creates excellent results.
the Nikon indoors with flash also creates very sharp and good results, but could use more DoF.
If I think about the amount of times I shoot events or go outdoors, I should go for the Nikon.
But I still want to go test more outdoors!
I once went out already with the Nikon, and was actually not so happy, specially when trying to take image of flowers, they never seemed sharp. But this could be blamed to me, for being to excited and forgetting to check my settings ^^