Depends on how much your going to shoot it in one session. In my case I shoot my 300 Win. Mag. for 1000 yard target shooting. In a practice session or a match you'll send 80 to 100 or so rounds down the pipe in a mater of a few hours tops. For this type of shooting with this caliber a muzzel brake is a must. If your only going to hunt with it and use it for only 10 or so rounds a year then you may not need a brake. I'll have to say though that the muzzel brake on the 300 Win. Mag. I shoot, along with a 1" Decel pad, that the felt recoil is about that of a .223. Also a brake will make the rifle alot louder, which for some is a problem.
If you intend to shoot your rifle in the prone position definately get a timed brake.
Here is a couple of pics of the brake I use along with the rifle it's on.