My humble opinion:
I thought Commodore's shinning moment was the release of the Amiga 3000. Some of my thoughts:
-They pushed the consumer, education, and workstation market with it.
-They ported Unix to it and did a great job of it!
-They had premier support services to make it more attractive in the Workstation market.
-The manuals were very well done; both the Amiga and AMIX manuals.
-They actually had advertising and media events.
-It looked like a workstation computer with both a desktop and tower version.
-Inside, it was really a good computer with lots of nice components.
-The higher-educational push was a great deal and helped to get Amiga's into some really nice universities. AMIX did exceptionally well against A/UX and other unices.
-Amiga Vision was a great product to combine many of these items together.
I just thought Commodore was at their best during this period. The computer was great, the articles favorable, Commodore's stock did well, and it felt like a professional Commodore with a great machine.
By the time the 4000 shipped, the market was much different. The Amiga was loosing market share rapidly, Commodore looked confused, and all of it felt different. Windows was really taking off and Commodore didn't seem like a contender anymore.
I sold my 3000 and bought a 4000. I loved AGA but the rest of it seemed iffy. About a year (more or less) later I sold all my Amiga stuff as the writing on the wall was pretty clear.
I also felt the Amiga 1200 was a great replacement for the 500 on the low-end.
-P