If I can make a suggestion, check out Kahntrol Solutions, yes it is my brother making them but i have them on several rifles of my own, if you go to the images page the AR-308 and the 30-06 are both mine. I also have one on my ar-15 that is in the middle of a rebuild which is why it is not pictured. I can honestly tell you the 30-06 is about like shooting a bolt 223 now, the ar-308 is about the same as my ar-15, and the ar-15 is just a joke to shoot.
reasons for clamp on
1- if made correctly and to the barrel it will be going on it is reliable, easily installed and when maintained properly it isn't going anywhere.
2- a muzzle brake by nature throws the sound out the side rather than down range which tends to tick off your neighbors at the range, IF your range allows them at all. therefore you may need to remove it from time to time.
3- if you need to perform work that requires more dis-assembly i.e. removing gas block on ar-15 you need that muzzle brake removable!
With the AR-308 i can honestly put 10 rounds minute of deer at 100 in 6 seconds, that is my reason for wanting all my rifles to have brakes on them.
If nothing else check them out and give us feedback as to what you think.