I use Google Sketchup for designing 3D stuff (Space Craft, Weapons, Cities, Buildings, ect). This program is REALLY easy to use. However, as I have read, the models in it can't be used for anything. I have tried Blender, but it doesnt seem to work like Skethup does.

Was mastering sketchup a bad idea? Should I try using blender again? How difficult is Blender compared to sketchup?