Coming from a CAD background, I actually find Sketchup to be a bit limiting, and actually a lot more difficult to do more complex objects than a CAD program.
Newer versions of AutoCAD let you do what Sketchup does, draw a square, and push and pull it. But you'll find it far more complex to use, probably much harder than Alibre. Then there's the $4K price tag. I also don't believe that most AutoCAD users don't use the Sketchup like features, as they actually just add a step to the extrusion process (the actual dragging)
I'd say that your parametric modelers like Alibre, Solidworks, etc. are the easiest to use. You just need to get used to the way they work, as they require a different thought process. But this is probably the best direction to head in.
So I guess that I'm saying, no, there isn't anything as easy to use as Sketchup. At least not that I'm aware of.