Kevin
Uncheck plant styles and draw 3D.
I think ram is more important. Also video ram.
I think 11 is an improvement over 10. There are still things that drive me crazy, like having to select plants from symbol list instead of a dialogue box of plant names - Robert, I know I am not the only one saying this, But all in all, it is better.
11.1 is as stable.
Major advancements - hmmmm, I would say it depends on your practice. I do more site planning than big, detailed planting plans.
Imports from 10 to 11 have been ok.
Definitely upgrade.