Hi Jeffrey
I have started shooting a 6.5-08 AI recently in 1000 yard f-class. I also have been shooting the 6.5x47 Lapua for the past year. Observations I can make is that 6.5-08 AI will push the 139-142 bullets at velocities that the 6.5x47 L will do with the 130 VLDs. So far, I have not seen an accuracy advantage or disadvantage of one over the other.
While most people using Lapua brass form the 6.5-08 using standard 308 W or 243 W brass. I have been forming it using the 308 Palma brass with the small primer and small flash hole. So far no ignition problems using H4831SC and Wolf SRM primers.
Barrel life on the 6.5x47 is excellent and you don't have to do any case forming. I weight sorted 2000 pieces of 6.5x47 brass and had a extreme weight range +/- 1 grain with the bulk of the brass falling into a +/- .5 grain weight. The neck wall thickness on the 6.5x47 is about .0002" less than the 308 W brass and because of chamber, I am turning necks down to .0120" thickness on the 6.5-08 AI. Too soon to tell what the barrel life will be on the 6.5-08 AI shooting 48.4 grains of H4831SC. The 308 Palma brass is definitely less expensive than the 6.5x47L brass.
The 6.5-284 does work and is well proven. How much life you get out of a barrel really depends on how your chamber is designed to begin with. If you start with a chamber designed around the Sierra 142 hung out,,, once the throat walks out, you have nowhere to go. If you start with a shorter throat designed around a VLD, you can start with a JLK or Berger VLD, switch to something like the 139 Scenar as throat moves and continue on to bullets with lower caliber ogives.
Arne