The recoil will be manageable without one, but it sure feels nice squeezing the trigger and the rifle barely moves. The 260's range on whitetail deer is limited to around 600-700 yards depending on the bullet and energy, but for target generally this round is good out to 1000 yards. A 140g bullet and H4831sc or similiar should get you up around 2700 fps or a little more. The re-sale value is in the eye of the beholder. If you decide to sell and the new owner doesn't like the brake it's very easy to cut the threads off and re-crown.
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I had the same question for my current build, a 7 SAUM. I decided to have it braked because I will need to spot my own shots and reduce the recoil so my wife can shoot it too. The report of the shot will be louder, but if hearing protection is used there is no problem. Might as well have the lowest recoil possible. Just my 2 cents.
I would NOT put a brake on the 260. I'm just guessing, but your rifle will probable weigh over 10 pounds. I don't think a brake is needed at all for the 260. Good luck with the rifle, I hope it's a shooter for you. Eric