I've been looking at both these cartridges also and my opinion is... I want both They are both close in performance and the 284 will slightly edge out the -06 in velocity, but will probably have a little shorter barrel life. If you go with the -06, you might want to go with the Lapua 30-06 brass and neck it down. It's a lot cheaper than the 6.5-06 A square brass. The Norma also has Lapua brass available.
There both GREAT! Rifles but you will need to have a lot of hand loads, I have 6.5x284 I love it a lot,I do a lot of deer hunting on our farm mostly every deer 1 shot just dropeded to the ground You are gonna need to hand load, can you go to the nearest Sporting shop no, so you will need to make the right load for hunting the 6.4x06 you will be in the same situation.
If you are going to make tiny holes on paper, it will be fantastic..I build a few rifles with with my older brother we have been very lucky. I cant say enough about this calibre.