I think the choice really depends on what you want to do with the rifle. For mid range shooting with conventional bullets many like the 264 better due to the higher velocity. For sheer long range accuracy using the best high BC bullets, my experience has been that the 6,5x284 typically trumps the 264 mag. For shooting from 50 yards to 1000 yards the 140 VLD's at 2950-3000FPS seems to be the sweet spot with excellent terminal performance on game over this entire range. This bullet seem to have been made for the 6.5x284, as it currently offers the best ballistics for this caliber, and, it is a remarkably accurate combo with a 1:8 twist. The VLD's tend to blow apart on game at very high velocities at closer ranges. At 500-1000 yards I doubt a mule deer could tell the difference between the two calibers. I think there are a couple of other benefits to the 6,5x284. As much as people comment on the barrel life of the 6.5x284, it's better than the 264. Recoil is nil, and it a cinch to load, particularly with good Lapua brass available.IMHO.