Hi Bill, I don’t think there is a significant difference in functionality of clones. I believe they all exhibit the faults of the original, although, like the original, there are some board to board variations in scope of the various problems. Replicas are a different matter, and it bothers me that most do not support cassette tape input/output, which puts those sort of replicas into a not really workalike category. I would argue that adding a Brain Board to an Apple II gets you closer to a true work-alike functionality than those replicas that lack cassette tape interfaces. Let me clear up a misconception. The only intentional difference between a Mimeo and an original Apple 1, is the logo I put into the copper layer on the back. There are some unintentional differences. 1) The modern PCB substrate and manufacturing process is different than the original. The original type substrate isn’t made any more because it is incompatible with modern PCB manufacturing processes. 2) A lack of information due to the non-existence of bare board original Apple 1s caused a few mistakes, most of which were corrected in later batches, as the mistakes were discovered. 3) The difficulty of reproducing a board that was laid out by hand taping methods which despite the great skill of Howard Cantin lead to some variation in the layout. Note that the Apple II was laid out digitally and was somewhat easier to clone. I have found it somewhat amusing over the years how Apple 1 clone makers have frequently copied mistakes made in various versions of the Mimeo. best regards, Mike Willegal