Muzz, It's a tough call to go Ackley or not. If i were buying a new barrel, i'd probably go the Ackley route as i'm a fan of the improved case, especially the improved '06 case which the 25-06 Ackley would be, and i reload anyway.
I have though, killed 8-10 nice Muley bucks and probably near 50 better class Blacktails with the Reg ol 25-06 and i loved every second of shooting and hunting with that round. I think it's only drawback is in it's lighter bullets at the longer ranges. There are better cartridges out there that can do a better job at distance. Up to 400, maybe 500 yards though, it's a buck killing SOB of a cartridge and a pleasure to shoot.
Good luck with yours!!
Joey
"It's all about knowing what your firearms practical limitations are and combining that with your own personal limitations!"