Is the CoCo 3 the best 8 bit computer ever made?
If you exclude sound, maybe you could make this case?
No, the C64 was. Obviously!
You made the claim, what is your case?
I personally think the Commodore 64 as it was best price to performance you could buy. There is a reason why they call it the VW Beetle of Computers. Heck they are making new ones.
If you ran OS-9, level 2, yes. Bank switched memory for 64 processes. Documented system calls. A windowing system.