Can't give you exact numbers right now because the toys are in my parents' place (no room to display my toys in my current condo). According to memory, the 1/144 scale FIX is slightly taller than the MSIA.
However, what is impressive is not the size, but the amount of panel lining and markings on the FIX. The FIX really looks like a painted model, while the Japanese MSIA (already with panel lining) looks like a plastic toy.