How can I select the best OCR engine for my digitisation requirements?

Impact CoCDigitisation for beginners, Discussions

I guess there is no “best” OCR engine independently of the purpose but, is there any protocol to compare their performance? Perhaps, the Centre of Competence could provide some sample sets and evaluation measures on those sample sets. If they provide sufficient coverage, probably my requirements are similar to one of the subsets and it can help with the decission. What do you think?