The 6.5X.284 appears to be slightly superior to the 6.5-06.
Aside from the fact that you can purchase loaded ammunition for the 6.5x284 (At great expense) I don't see how.
The 6.5-06 case is larger, (by about .4 cc usable space), and my Hornady manual shows about 100 fps higher for the -06 in just about all bullet weights.
According to Hodgdon, both will launch a 140gr bullet around 2800 FPS and a a 160gr around 2700 FPS, so at worst, they are equal.
The 6.5-284 in theory can be chambered in a short action, but with a long bullet you probably won't fit them in a short action magazine. The .284 is fatter, which in theory is better for accuracy (short fat powder column) but the magazine will hold fewer rounds.
It is pretty much a wash.
If you go to YouTube there are plenty of hunting videos of the 6.5 x 284 NORMA taking game a long ranges. I believe the hunter uses the 6.5 x 284 NORMA on this long range moose shot.
The comments say it was a 300 mag. And you will never convince me a 1100 meter shot on game is ethical. I wonder how many he crippled before he got that one.