Of course the optical readers aren't immune to problems either. There was the SAT problem earlier this year where a bunch of tests were mis-read. And it's still possible to compromise a machine or higher up the ladder.
However, an optical reader has the distinct advantage that it's starting from the paper record to create the electronic record rather than vice-versa. (One of the problems with DRMs with voter-verified paper balots is what to do when the paper record doesn't reflect what the voter selected.)