Sketchup is designed for architectural sketches. The modeling grammar is nice for some operations but Sketchup is not really a well rounded modeling package. They are trying to move into construction.
IMO, main advantage of Sketchup over Autocad are a free API to access the model (although the domain model is not entirely well designed) and a fairly limited context of user interface operations (which makes the learning curve lowish).
The most critical difference though, is that Autocad supports actual analytic shapes while Sketchup handles only boundary representations (i.e. polygon meshes). No real cylinder for you! This may or may not be a problem.
IMO, main advantage of Sketchup over Autocad are a free API to access the model (although the domain model is not entirely well designed) and a fairly limited context of user interface operations (which makes the learning curve lowish).
The most critical difference though, is that Autocad supports actual analytic shapes while Sketchup handles only boundary representations (i.e. polygon meshes). No real cylinder for you! This may or may not be a problem.