I own Nikon 70-300 G, Tamron 70-300, Nikon 55-200 VR, Nikon 70-300 VR and Tamron 70-200 f/2,8.
In my opinion best buy is the 55-200VR, if you have a tiny budget. Sharp, light and compact. An all for less than 200 Euros
If you can spend more, I would recommend Tamron 70-200 f/2,8. Not very good at f/2,8 but spectacular at f/4, much sharper than Nikon 70-300 VR. Its focusing speed is OK for me.
Good luck.