New 18-300vr or 70-300vr?

I already have the 18-70 ( a great lens) and was looking to get the 70-300 vr for travel.

But the 18-300 is around the corner and makes me wonder:
Should I:

Keep the 18-70 and add the 70-300 VR, (which was my original plan)

OR

Sell the 18-70 and get (and wait for) the 18-300 VR to have a one lens travel solution?