I recently got a used IBM Model F AT in quite good shape. It really is incredibly responsive. The SysReq key, probably not much used, especially feels amazing, but even the well used home keys are more responsive than the keys of the Model M I bought NIB.
All that said, it is really loud, even compared to the M. And I'm wondering if the M, which still has an excellent, if humbler, implementation of those world beating buckling springs is a better compromise...