6 of one and half a dozen of the other. Both will shoot 120 ish grain up to 160. Both will shoot flat enough and both will have enough thump to take any European game provided bullet is in the correct place. 6.5 might shoot a bit flatter, but probably makes not much difference in practice.

Exact same argument with 6.5x55 and 7x57, or 260 rem and 7mm-08.

Which of the two rifles feels nicer, fits you better, has better sights should be the determining factor. Ammo availability may be a consideration as well, but get a set of dies and 50 cases and you will be happy for a long time.