Facebook just released the new Facebook Messenger app, to be used in conjunction with their regular app. Messenger strips away everything except the basic chat and messaging features, which have recently been merged into one entity on the web site anyway, so I suppose it makes sense.
The app itself is very basic. It's pretty much the exact same thing you'll find in the message and chat sections of the regular app. The regular Facebook app has tons of issues of its own, from notifications coming extremely late to the very slow load times, among others. By creating a dedicated messaging app, they can get rid of the clutter and improve the stability and performance of the messaging itself, which is a welcome change. When used with Wi-Fi, the messages are almost instantaneous. The app works great for one on one conversations, but switching into group threads will probably devolve into the same message tagging that you're used to. I'm sure using the phone network instead of Wi-Fi will slow things down a bit, but not by much.
A new addition to the app is the ability to share your current location. I could see that being very useful in some specific situations. You can also upload pictures from your phone directly into the conversation, or you can immediately take a new photo. The Android version of the app has the added ability to search for photos online, absent from the iOS version. The app is lacking one major feature though. There is no way to see who is currently online. This is ridiculous considering that the same feature is present in the normal Facebook app. Otherwise, there really isn't much to say about this app. It's very simple and bare bones, but if you're a Facebook user, you might as well pick it up and try it out. It's not the best messaging app in the world, but it's free, and it's Facebook. Check it out.