I use to own a MAMS for my Mod1, and IMHO, it is not worth the price.
I've owned and used plenty of muzzle devices, and have concluded that the Precision Armament EFAB is the best overall muzzle device if it is to be used without a suppressor, as it can't accept any.
Since you are already set on getting a KAC suppressor, you will be limited to KAC MD's.
It depends on how you use your rifle and suppressor... if you have the can on it 90-100% of the time, then IMO there is no need for a MAMS.
The FH will accept the suppressors just fine, and if the suppressor is on the rifle most of the time, there is no functional advantage to have a compensator like the MAMS.
But again, since you have the 14.5" barrel, and if you decide to do P&W... IDK... it really depends on what you value, and what you think looks/functions better, as the MD will be on the barrel for good(at least semi-permanent).