I have a 338-06 AI under construction, so it will be awhile before I have real world data. I did order Norma 338-06 headstamped brass. It holds 71 grains of water to the case mouth. If the AI version gains 7% capacity, final case capacity should be around 76 grains.
Research I have done regarding 338-06 chamber dimensions indicates that there will be enough freebore to seat long bullets, such as the Berger 250 and 300 EH, even with the case neck (or nearly so). Though I probably will not use bullets of this weight for hunting, I expect them to be good long range practice bullets at reasonable cost.
I am taking a hard look at the Cutting Edge 338-200 MTH. It is made to be seated to 3.340", so it will feed from the mag. Based on QL calculations, I should be able to push it to 3000+ fps from a 26" barrel, using RL-17. With a .570 bc, that should make for a heckuva combination from a sporter weight rifle.
I am interested in trying the Rocky Mountain 225 ULD's, though they will be too long to mag feed.
When I am able to start actually burning powder, I will share my results.
I believe the answer to your question will ultimately be dictated by what you want from your rifle and how you intend to use it.
In my research, the prevailing sentiment is that the standard 338-06 is good enough for most purposes. If more is wanted, most seem to feel that stepping up to .338 Win Mag makes more sense than the 338-06 AI. Most folks stating that opinion seem to be using standard hunting bullets at <400 yards. For this application, there seems to be a lot of back-and-forth between 338-06 guys and 35 Whelen guys.
I am going with the AI because I am trying to squeeze all of the performance I can from the -06 case. Depending on where I end up vs my performance objectives, I may try going to the .280 case to get just a bit more.
From what I can tell, the standard 338-06 and the AI version should be within about 2% of one another. Which one you decide to go with depends greatly on how badly you want that extra 2%.
Be sure to try VV N-550 in the .338-06 Ackley. A friend at my Range Club has a 24 inch barreled rifle chambered for this cartridge. He is getting amazing velocities with the VV powder. He is using the 225 boattails (Speer) and I have seen great groups at 200 with a 3-9 Scope. The Nikon and Leupold scopes have not faired so well on this rifle but the velocities are amazing. Brass life has also been an issue. One trick he has tried is to use Remington .35 Whelen brass because it is rated at a higher pressure by SAAMI. Lately he has been using Norma '06 brass. I would look at Nosler .35 Whelen brass.