They are both good at their own way, the Bitcointalk is an old forum where people trusted for long period of time people earned a lot of money thru cryptocurrencies because of this forum but they system, of course, changing as we knew nothing is permanent in this world rather than change.
Well, Altcoinstalks is good enough for all of us especially those who are just starting at cryptocurrency because there's the only couple of restriction compared to the Bitcointalk which newbies are loving so.