So I've learned my first painful lesson concerning lenses:

Tele lenses without stabilization are only usable with a tripod.

I'm going to send back my Sigma 70-300mm F4-5.6 APO-M DG Macro. I've just got too shaky hands and being able to shoot 300mm at a shutter of 1/300 only is with a max aperture of f/5.6 pretty restraining.

I'll get the Sigma 18-250mm F3.5-6.3 DC OS HSM instead. Maybe less quality but I need it for travelling anyway and convenience is more important for me in that case.

P.S. No, Nikkor ain't in my price bracket. ;)