If it is primarily for long range hunting I would go with 6.5-06 A-Square. Unless you just like ancient history or you enjoy a lot more work for not much more return on your time and investment leave the AI nonsense alone. Gaining 100-200 fps is a waste of time when you look at all the con's of AI cartridges in light of it now being 2018. We have far better powders that Akley had in his day and most people are not sitting on a ton of military surplus brass and powder like he was. On top of that until you get into boutique cartridges not based on really common cartridges brass prices are fairly level so 30-06 brass is not much cheaper than 300 Win Mag brass for example. So by the time you factor in buying roughing and finish reamers, much more expensive dies, the shortened case life, shortened barrel life, all the extra time in case prep AI's cartridges make no sense. When you look at all the short fat and standard length fat bodied cartridges we have as well that are not wildcats again it makes the AI road look pointless in almost every way. This is not 1960's or 1970's better options are commonly available.
When the picking where slim cartridge wise and surplus brass and powder where common it made perfect sense. When I was a kid sometime the next step up from where you were at already was an insane step up there often was nothing in between mundane and Weatherby Beast! LOL That is not the case today in 2018 and it has not been the case for a few decades now.
In competition, I could see maybe favoring the 6.5-284 because more top shooters use it and "theory" says it should be more accurate due to the shorter fatter cartridge brass as compared to the longer thinner powder column in the 6.5-06. I am not saying I believe that to be true but unlike a lot of things in life the sample size is too small and the number of variables in that sample too large to make anything like a true educated guess based on anything statistical!
I think Mr. Akley just liked playing around and hot rodding the mundane I do not think he was saying " Hey this is the best possible option and the smartest way to go so everyone follows my lead!" I think it is interesting that no one on either side of the Atlantic has ever made any of the AI cartridges an official cartridge as far as I am aware yet plenty of wildcats have been made into official cartridges that are certified and standardized! You could hot rod the low-performance Chevy 305 but you would be far better off with a different GM engine design as your base. Likewise, you can get some trick heads for Ford Model T 4 cylinder and for Ford Flat Head V8 but again far better engines exist today that would make better power more affordable and would be more durable. Same thing with AI cartridges.
If it was 500fps more than it would make sense. We get higher velocities today out of just about every cartridge than they did 1950's-1980's because of the far better and greater variety of performance powders with burn rates better suited to each cartridge!
I seriously doubt you will see 200fps more with the 6.5-06 AI. Your rifle and barrel play just as an important role in what you see in terms of velocity.
At the end of the day it is your money you worked for it and things do not always need to make sense! In my 20's I used to put V8's especially Corvette engines in various imports especially Toyota trucks and sport utility vehicles and I also would do turbo V6's in various imports both European and Asian. TOday and 45 you could not pa me to do that! LOL That said I can buy many imports with V8's and turbo or supercharged V6's or just high compression direct injection V6's so I do not need to do that. In fact todays I4's make as much power as a lot of V8's and V6's from the 1970's, 1980's, and 1990's. A lot of V6's make the type of power today you needed a V8 for 10 years ago. Times change!
P.S. I used a 6.5-06 for almost 20 years for hunting and loved it. I am getting ready to build that rifle into a 7mm Express/280 Remington. I had one before and I let it go it was again fantastic. You know what they say 6 of one a 1/2 dozen of another! LOL