Most of my animations that have been created in the past have been for demo or proof on concept purposes. More complex animations within Solidworks can be sometimes incredibly difficult, however they have introduced a number of new features recently which does make it easier. Normally I would use Solidworks for physics based questions, i.e. motor forces and torques. Its also useful for understanding complex motions that would be hard to concept without motion.

Motor Chassis Lift
FANUC 430 Robot Motor Force Calculation and Motion Check

The normal approach to more complex animations which relate to technical illustration media or marketing material would be to use a package called Solidworks composer. I have produced numerous sets of documentations for many industries using this package.

Boss Tower Assembly Guide using Solidworks Composer
Assembly of a Multiplexer Card

I also can use a package called Solidworks Visualize for creating high quality renders and basic rotation animations. An example of an animation in Visualize can be seen on the Automotive page.