It's all pros and cons. F122 are not all metal and not as heavy, but they are indeed quite nice.
Beamspring are not ANSI (and nearly completely inflexible layout unlike an F/M), ABS caps (which I like but some do not), unergonomic, difficult to find replacement parts for, and unreliable (their PCBs are more sensitive to dust and they are less airtight).
All are great keyboards, but different keyboards.