I have seen so many Magna-Ported barrels that were not kept clean and damaged from shooting that I do not recommend it.
They are harder to clean as the gunk seeps back into the rifling... and dust and debris also enter the ports... when the rifle is fired in this condition, slight damage results.
If you have one ported, maintain it well.
I much prefer a removable muzzle brake. They reduce recoil more and are easy to clean.
The Magna-Porting, the Muzzle Brake, and a bare rifle all damage your hearing when fired. Use protection with all of them or suffer the consequences.