Visit a bricks and mortar shop and take a few shots at assorted focal lengths and apertures and have a good look at the final results (print, monitor etc) to see if they are up to what you want or need.
IMO, that range is just too long to keep the quality but I have NO personal experience of the model and lens designers are very clever these days. Try to include areas wher chromatic distortion is likely - the long stretch zoom I used to have was pretty horrendous in that respect, even stopped down and in the middle of the zoom range.
Your money though. Personally, I would try to find a Nikon 18-70 in a second had cabinet and team it with the Tamron 70-300 - maybe with a wiew to upgrading to a Nikon 70-300VR. OK, I'l stop spending your money now!