I've been using this app for some time now, every since it became more or less stable. Sure, it may not have access to certain things, like inbox, but what it has - it does x100 better than official app. I happen to have the beta version of the upcoming release, and the chat has been already implemented. The updates are not as frequent as I'd like them to be, but the quality of each update is superb. Give it a try, and I promise, the only thing you'll go to official FB app for is contact sync and occasional inbox visit.