>CB is purely an image based captcha solver using OCR.
Not quite right. Where the competitor uses "only" 2 ocr engines, CB uses more than 2 and also uses there own filters (all self coded and not using external programs) and it can solve some captchas without OCR (2 algorithms included by now). OK and while Im at it, all the ocr results are compared char by char and a decision is made which one to take instead of taking just one result as seen on this CS program. Resulting in a way more correct answer.