i have both....both are pretty stiff shafts. the mezz is lower deflection, if that's an important criteria for you. the mezz is also slightly thinner at 12.5, the edge is 12.75, though you can order it in thinner dimensions. an edge shaft at 12.5 might possibly be comparable in deflection to the mezz, but i haven't tested an edge at that size.
i like the hit of the mezz better, more solid, more like a maple shaft. the edge has a more hollow, plasticky hit due to the ferrule.