I have used tesseract and in my experience unless you train it for the particular type of text you want to recognize (font, background color, etc.) it will do quite poorly (including the recent lstm based versions). Would be great to see how it stacks up against these APIs though.
The supplied models are trained on document-like images, so I wouldn't expect it to do particularly well on things like street signs. My experience with the new lstm based versions is that it's very much competitive with closed source solutions for document-like OCR.
