The Samsung Galaxy S4 Active features a wide array of advanced features and applications that really make it stand apart from other flagships.
One of the coolest apps is called Group Play. It shares various multimedia across multiple devices in the same room, but unlike DLNA it's interactive.
One use case is to play a music track on the Galaxy S4 Active and use multiple phones as speakers. You can pick the role of each phone (e.g. left channel, right) all the way up to surround sound. This way you can control the music from one phone but use the loudspeakers of all.
Of course, the other phones will need to support Group Play - the phones communicate over Wi-Fi (your Galaxy S4 Active becomes a hotspot that others connect to) and the pairing is done via NFC.
More useful are the options to share a picture or a document - you can have the same picture appear on everyone's phone and you can draw over it if you need to highlight a certain element of the image.
Finally, perhaps the coolest feature of Group Play is that it allows for multiplayer games to be played on several phones simultaneously. Of course, only supported games work - there was a poker and puzzle games preloaded on our unit.
Moving on, there's Samsung Link, another way to share content between devices. Unlike Group Play, Samsung Link is intended for personal use. You can link the phone to a computer that is synced with Dropbox, SkyDrive or SugarSync and remotely access content on that device.
S Translator will help travelers - it can translate between two languages using either typed text or by using speech recognition. It can read out the resulting translation too, if you don't think your Korean accent can cut it. S Translator supports all the widely-spoken languages - English, Chinese, Spanish, Portuguese, French, German, Italian, Japanese and, of course, Korean.
Samsung WatchON is the primary app used with the built-in IR emitter on the top of the phone. The app starts out by asking your zip code and pulls up a number of TV service providers in that area.
This is so that the app can show you a TV guide with shows currently on or upcoming on the channels offered by the service provider. You can read a description of the show, check out its popularity in up/down votes (and vote yourself, of course) and comments. You can also set reminders for shows you want to watch.
Anyway, the key element of the app is the IR remote control functionality. The app can control TVs, DVD and Blu-ray players, streaming media players and air conditioners. Devices are organized by rooms.
One thing we really liked about the app is that it knows some home setups are messy - some let you change channels with the TV remote, others require you to use the set-top box remote for that. Same for the audio, you might be using the TV to output the sound or an AV receiver. The app will ask about your setup and present a unified remote control interface even if you have multiple hardware remotes to control all the devices.
Finally, S Health is Samsung's home-brewed health and fitness tracking application. It starts off by getting you to create a profile which includes all your vital statistics, such as age/weight/gender and level of activity, plus your calorie consumption goals.
It provides a pleasant interface which gives you an at-a-glance look at your progress, as well as walking, exercise, and fitness trackers. S Health also supports a number of optional accessories, which enables it to give even more detailed info on your status. This includes scales that wirelessly transfer their measurements to the phone, where you can see a graph of how you're doing.
You can use S Health to track what you've eaten for the day and how many calories you've burned during exercise (with many different types of exercises supported). It also measures your comfort level by keeping track of the temperature and humidity around you.