It's alright and has the potential to get better but at the moment it lacks capability.
Currently there are next to no compatible Australian apps available with the exception of 7plus. Adding all the freeview apps (Nine, Ten, ABC & SBS) would bring it somewhat in line with Apple TV and make the firestick much more functional and useful.
Likewise there's no built in functionality to cast to the firestick like the chromecast. There are a couple of apps that adds this functionality however they dont really work and the cost money/have adds. It would be convinient if Amazon could develop their own free app to add this feature.
The "app store" is basic and lacks usability, there's no ability to search apps with the available apps just being scattered below your downloaded apps and on a second screen. Having access to the Google Play store would be beneficial, at least until Amazon is able to offer an equivalent. As it stands the Apple Store and the Google Play store are vastly superior.
The home screen is messy and unorganized, the top line has your downloaded apps then below are the apps available to download. Having a dedicated home screen with all of your downloaded apps and then having an App Store icon on the home screen would be much tidier and more functional.