Having been an inhabitant of both the MR and HH threads, FT's HH elites tend to be very breakfast focused and oriented.
So, if you are breakfast-centric, HH Diamond may be a better place to be. That being said, variations in service and quality across all of Hilton's brands may drive some elites nuts. If you like a more consistent service level from stay to stay, you're more likely to want to be MR Platinum.
And if you're SPG Ambassador, you think everything else is garbage.
David