Hi wonderful,
I think that ptc site will not be good thing to earn if you want to earn in legit ways. Because, many ptc sites are turning scams, it is difficult to win the trust of the members and so earning is also easy.
However, if you go for a forum, it may take longer time for you to earn money as well as good reputation. But once your forum gets good reputation, it will be easy to find good sponsors and good faithful members. Perhaps forum will require some good investment too but I think that it will be worth.