I am using Blender professionally in combination with Unity on a daily basis.
Blender doesn't save shapekey information into animations clips when you export a model as an fbx file.
Additionally, shape keys are much, much more heavy on performance than bone animations. So shape keys are not really an option for me as a game artist.
If you're producing pre-rendered CG animations, then use a clever combination of both. If you're making a game, try to stick with bones only.
Somebody correct me if I'm wrong.
Also, does anybody know how to properly weight paint faces with classic bones only? There are literally no tutorials on advanced face rigging on Youtube. Neither are there commercial tutorial DVDs that explain the process properly. In Blender you can have an endless number of bones, each with a full weight of 1.0, on a single vertex. That shit causes all sorts of problems when weight painting. How is a guy supposed to properly rig a mouth for example? I always end up with a huge clusterfuck of bone weights everywhere.
A nudge in the right direction would be much appreciated.