OCRopus
OCRopus is a collection of document analysis programs, not a turn-key OCR system. In order to apply it to your documents, you may need to do some image preprocessing, and possibly also train new models.
In addition to the recognition scripts themselves, there are a number of scripts for ground truth editing and correction, measuring error rates, determining confusion matrices, etc. OCRopus commands will generally print a stack trace along with an error message; this is not generally indicative of a problem (in a future release, we'll suppress the stack trace by default since it seems to confuse too many users).