Verified answer

Sketchup creates figures that are mad up of planes - everything in Sketchup is actually two-dimensional, like a sheet of paper. Solidworks is truly three-dimensional and much more useful for engineering purposes - you can do things like calculate moments of inertia, stiffness, weights, and strengths of the solids that are created in the program. It is considerably harder to learn than Sketchup.

Sketchup To Solidworks

I use both every day. Solidworks is fast for 3D design, but autocad is much better at making 2d production drawings. So I design in Solidworks then make shop drawings by exporting geometry over to autocad. So I'd say go for the Solidworks if you can, because you can always use their lousy 2D interface to make 2D production drawings...you'll just have to fight with it more it to get it to look right.