I've seen it but I personally have not used it. It does look pretty amazing. At work we're on Creo Parametric 3.0 in the process of upgrading to 5.0 (once we resolve the visibility and GD&T issues). We are buying seats of Topology Optimization, but since it's not available until 5.0, I haven't had a chance to use it. Obviously Additive Manufacturing has a ton of benefits in many fields (especially aerospace) and Topology Optimization holds a lot of promise.
I've been using Onshape for a couple weeks now. I'm impressed with the ease of part- and assembly- modeling, and the data management and collaboration tools are game changers. I haven't explored any of the apps yet but I'll take a look at CAEplex.
If you're analyzing a mechanism, you would probably be using the Mechanism Dynamics Option (MDO) in Creo Parametric. Back in the day that used to be part of Mechanica (the precursor to Creo Simulate) but now it's its own separate module. With MDO, you can perform Dynamics analysis that incorporates mass / inertia, springs, forces, moments, and so on.
You can take the resulting forces and use them as load cases in Creo Simulate, for example, in a static or dynamic time-varying analysis.
Creo Simulate can be used to perform analysis on both parts and assemblies.