If you ask me, Tapatalk is pure epicness, especially if you have several forums you visit frequently. However, it's a forum app. That said, you can only use the forum. Not view photo albums, see notifications etc. The chat is out of the question as well.
I use Tapatalk all the time, and complement it with a phone browser when I want to see the non-forum stuff. PM works with Tapatalk also.

You find the application in Android market or Apple market