Despite its sleek look, the default Facebook app on phones can be bulky and slow. Facebook Mobile With Chat is a free app that claims to get you faster browsing and posting, but you probably won't notice those improvements. What you will notice are the ads that Facebook Mobile With Chat litters your phone with.
As expected, you need to sign in with your Facebook credentials for this app to work. Once you're logged in, the app is the spitting image of the regular Facebook client. Everything is laid out exactly the same and the speeds aren't noticeably faster or slower. The only thing you'll notice that is different with Facebook Mobile With Chat is a banner ad hanging out at the bottom of the page. The app sticks ads into your status bar every so often, too.
This app really is no different than browsing Facebook from the official app. The only thing it adds to your Facebook feed is bonus ads, which definitely aren't a plus. With few, if any, benefits, there's little reason to add Facebook Mobile With Chat to your mix of apps.