I used the Automark machine at my local polling place (U-M Coliseum). I've used this machine before many times, so I have figured out the easy parts of what can go wrong – for instance, on this machine you have to take the tab off the ballot before inserting it. But this time things went wrong, and I'm not 100% sure that my vote was counted when I inserted it into the tabulator.
The actual practice of voting went fine. It's a long ballot, and I went through all of the eleections, in some cases undervoting the ballot (see "plunking") and in other cases not voting at all when I didn't know anything about any of the candidates (my bad).
The touch screen on the Automark device that I used didn't have perfect registration, and so every so often I'd hit a button for one candidate adn it would mark the other one. You'd think that you could design a screen so that the ballot "hot spot" for each candidate was further apart, don't you think? But I was careful and made sure to vote for the right candidate each time.
The first problem occurred as the ballot was being printed. The printer went kachunka-chunka and printed both sides of the ballot, but then it stopped with an error message to call an election official. The very nice election officials didn't know any more about the error message than I did, so we decided to pull the machine apart to extract the printed ballot, and if it turned out to be wrong to spoil it and start over. It came out OK, I double checked it and it was printed on both sides, so it looked right.
Next, time to insert it into the tabulator. Usually you insert the ballot into the tabulator from the top, right? But the tabulator wouldn't take the ballot. I then put it in backwards, and the machine accepted it. I just hope that it read it correctly.
It wasn't a confidence-inspiring visit to the polling place.