I have used it a little, it's ok but your limited with the amount of surfaces that can be used. It is worth playing with it so that you get a feel of how to work the basics of Mechanica. IMO I wouldn't drop it like I would manikin.
Sorry I just have to respond. Usually I'm a big defender of PTC I still believe Pro Engineer is the best CAD package to be had. However when it comes to FEA work just the concept of a lite package should give concern. I like Mechanica, but it is no Nastran/Patran or Ansys and it has limitations. A lite Mechanica, its bad enough that people don't understand the limitations of a full version of Mechanica. Yes these things give results, but unlike CAD modeling seeing should not necessarily be believing in FEA. So depending on your application I would choose something more robust where you have real confidence in the results based on the limitations of the underlying mathematics.