Hi Phil,
V8 was a good version, best since V4. V10 added a lot of flexibility in editing so it was great and V11 just refined a few things. I avoided V9 completely because of all the bugs reported by users and while I cant remember any specifics now, I know everyone found it very frustrating. I dont think a patch was ever released, they went quickly to V10.
V12 and now 14 are just as easy to use but capable of even greater things. Essentially they are Envisioneer 5 without the CAD and technical plan printing functions that multiply the price by 15 times! From either Floorplan 3D or TurboCAD you may be able to get an Upgrade price if you plan to do some serious design work. Worth a phone call to check as the upgrade discounts are usually very generous, certainly from the more recent versions.
What sort of things were you wanting to do?
Allan