If lapua doesn't make brass for it, I don't shoot it in competition. period. life is too short to muck with cheap brass. For that reson alone I would go 6.5X47 Lapua, but I have also had a 6.5X47 and loved it. It is too small for the high BC, heavy& long 139-142 bullets that are the ticket in long distance shooting.
creedmore is tougher to find.
Don't forget the fantastic 6.5x55 swede or the 260.