[Android Apps and Games] ahrion:
Okay so I did some testing.

The official and Chiaki apps are very basic, but work. No key mapping, hotkeys, etc.

PStreamer is the easiest to set up with the easiest and best looking interface. It is the worst in terms of stream quality and input lag (it's not bad just not as good as the others), however I still like this one because it is very stable (stable release). Has the least amount of customizability and doesn't have the ability to set hotkeys (button + button = in-game button). However you can map gamepad keys as well as customize on screen buttons. It doesn't have the ability for voice chat currently. Allows on screen button rumble, but not rumble when gamepad input is used. Allows multiple input profiles for gamepad/on-screen. It allows multiple PS4 profiles. Allows functionality on Android TV and mobile data, and hardware decoding. I've been using this one for quite some time.

PSPlay is easy to set up, but not as easy as PStreamer. It has a pretty decent interface, but definitely not the best. It seems to be tied with REPL4Y in terms of stream quality. Input lag is minimal and better than the others. It seems pretty stable despite being in beta. It has an insane amount of customizability, especially when it comes to on screen and gamepad mapping, and has the ability to set hotkeys. It doesn't currently have voice chat. Allows in screen button rumble, but not rumble when gamepad input is used. Allows multiple input profiles for gamepad/on-screen. It allows for multiple PS4 profiles. Allows functionality on Android TV and mobile data, and allows you to use your phone as a controller only, and hardware decoding. I just started testing this one, but it will probably be the one I use in the future.

REPL4Y is the most difficult to to set up by far. It's kind of confusing, but not actually hard to do. Not a fan of the interface. It's tied with PSPlay on terms of stream quality. Input lag is minimal. It isn't very stable as it seems to crash quite frequently. It has a lot of button gamepad button customizability, doesn't require sign in for PSN, has the ability to set hotkeys, only one with PIP (picture-in-picture) mode. It is the only one with current voice chat functionality (no PTT). It allows both screen on-screen and gamepad button rumble. It allows for multiple input profiles for gamepad inputs, but has no customizability for on-screen buttons. It allows for multiple PS4 profiles. Allows functionality on Android TV and mobile data, and hardware decoding. I won't use this one until some of the kinks are worked out.

My daily driver will be either PStreamer (what I currently use) or PSPlay. PSPlay seems to be (so far) the better out of the two - by a Longshot (minus interface), with the most customizability for bitrate, dividing, audio, input, lag, etc. REPL4Y has some unique features, but needs some work in the development space. I like the idea of PIP and voice chat, which REPL4Y has, but it lacks the stability and some basic functionality such as remapping or customizing on screen buttons, along with frequent crashes.

Man if y'all devs pulled together, you could probably create something even greater.