@Franko
Depends on how you look at the question.
Current usage ... I use OS4.1 the most.
If I look at this question as which Amiga OS did I use most since 1985:
1st place goes to OS 3.1 on my A2000HD
2nd place would probably go to OS 1.3, the original OS on my A2000HD
3nd place goes to OS 4.0 on my MicroA1
4rd place goes to OS 4.1 on my MicroA1
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redfox
