One, that it is more suited to this loading case, and Two, that none of the people experience in ProMechanica contacted had suceeded in learning to use the Dynamic Analysis module yet. It's best to reduce loading conditions to this before you sit down to work out and analysis. Simplification ProEngineer is great for drawing complex, well-defined parts for manufacturing. ProMechanica is great for performing FEA on those parts. This comes with a caveat, however, that each nice complex element added to a ProE drawing adds multiple finite elements to the analysis.
More elements adds more time for each analysis.
A roughly 300 element analysis can run long enough to go get a cup of coffee. Since each element must be compared to all of those around it, the time required for a part to be fully analyzed does nto scale linearly with the number of elements. Rather, it increases more quickly, in some cases, than the number of elements. It is important to use simplify ProE drawings and to employ basic statics to find loads at sections of the part so an analysis can be broken up into joints to key areas. It is a linkable application, like several other available from Parametric.