Ross Schuler makes great brakes for the best price. I use one of his 3 port Holland style on my 338 Edge. It works great. Awesome deal for $40. Here's a picture of his latest ones.
I have the DE brake on my 338 rum built by Defensive Edge - I also have Jims 3 port brake on my Remington Sendero 300 win mag. While both are very effective brakes I would say their is less felt recoil with the DE brake on the 338rum. My rum weighs in at around 9# with the scope on it.
Sorry - I have no experience with the muscle brake.
Tiikamike, here's a link with a pic of 3 port and 5 port PK brakes. I believe Kirby bores them out 20 thousands bigger that caliber diameter in any finish you want.
I dont wanna hi-jack Mike's post, so Ill keep er short and sweet.
Jmden, would that tiny one work well on a 300wby? What do you have it on?
Sorry Mike.