Pros and Cons? Use them both?
Use them both if you are able. If you are not able to use them both, use bitcointalk.org.
actually my question for OP mate is why need to use altcoinstalk when everything we need is already in Bitcointalk?
there are so much happening here from bitcoin market to thousands of altcoins around the globe so i guess it is just a waste of time to consider using 2 unless you are a typical BOUNTY HUNTER that only uses Sites for bounties and not for investings .