There are some other new opened bitcointalk like who really trying to make and clone bitcointalk.org which they cannot beat on, I guess there is no other good paying forum as what we have here. So why looking for another one? This forum is trusted by thousands of people.
We have already well known clone of bitcointalk called bitcointa.lk (beware of that site, they are not using SSL and there is high chance your personal data will be stolen).
There are also other forums which want to copy bitcointalk to gain financial profits. We know users who were banned on bitcointalk and went as far as to create their own version of the forum.
But if you really have to use other forums - just use Reddit.