I never liked any of them until the 6 and 7. To my ears, the 3/2 was a painful listen and the 5.1 wasn't much better. Things changed with the 6 and 7 which are two of the best speakers I have ever heard. In my opinion the 8 was a step backwards and, if memory serves, it didn't stay in production as long as the others. I actually prefer the iterations of the Sophia. Good luck with your search.
Wendell
Wendell