I must admit some of the those points sound familiar. When I started using SU the two most frustrating things were the "sticky" nature of objects, which does mean that you have do make everything into a component, and the sizing of things. If you are used to CAD, like me, it really can be very frustrating trying to get accurate results in SU, and I think that highlights the way it differs from CAD. Most people like it that way, as its less formal, more "sketchy" and really quick and interactive. I still find it surprising how fast you can edit a 3D drawing in SU, which makes it a great design tool. For accurate scale drawings, in 2D, CAD is far better though.