In terms of the 'numbers' I would expect it would favour the 6.5 - a much more popular caliber for long range shooting / high BC bullets. The biggest difference would perhaps be that 270 Win is one of the most popular factory cartridges around, whereas the 6.5-06 is obviously (still AFAIK) a 'wildcat'. If you're already set for a rifle, and don't care about factory loads, then perhaps that won't matter to you. Otherwise, they will be pretty close in all things, as one might expect given the near identical cases and .007" difference in bullet diameter.
