I am starting a project to develop a Question & Answers web site. Although a framework by itself does not ensure the success of the web site, it is clearly an important choice if you don't want to spend a lot of time with things that were developed before. From my research I discovered a list of Stack Exchange clones.
From this list, it seems that one option could be Question2Answer.
Advantages (for me):
PHP & MySQL development (As far as I know, but it could be Java or Python as well)
Topics and tags
Deal with security issues.
Desirable (I don't know = I investigated Math homework (developed using this framework), but I was not able do be sure about these below-mentioned characteristics):
Gamification (Badges and reputation scores)
Users with different kinds of permissions
Statistics about page visits, number of answers per week etc
I don't know any disadvantages for now.
Based on the requirements I am looking for, Question2Answer is a good choice? If it does not present all these characteristics, is it able to develop them?
Is there another good choice that presents these characters or ease of development of them?
If there is no free source framework, is there a good choice for a paid framework? [Among them, it seems that AnswerHub is an option, but it seems be a kind of expensive decision to be made before starting]. Is it really a good option? Are there other good options?