As a former minority clerk for Ward 14 District 8 of the County of Allegheney, I can say that the old voting machines had their problems. They break easily. They're too big and heavy for most of the people who work at the polls to move.
But did they ever leave a paper trail. Copies and more copies. Those who work at the polls arrive at 6:30 am, spend the day supervising the elections, then, when they polls close, they tally the votes. It is the day from Hell, especially when it's a presedential election. ANYTHING that would make it shorter is good.
Having said all this, these new machines make it too damned easy to rig an election. Never mind the Republicans. What happens when a gang of anarchists hacks into the machines, and fixes it so the good people of Cleveland elect Mickey Mouse, Donald Duck, and Goofy to high municipal offices? Do they hold a new election? The right could find themselves skewered with their own spear.