I've personally used multiple YouTube apps on my Lumia 830, so I will share my experiences with each app here.
1) myTube!
Currently the one I'm using.
PROS:
- Smooth performance, easy navigation
- Supports background playback
- Dark/light theme with color customization (can even set to follow phone's color scheme)
- Download videos or audio of videos for offline playback (the file can only be accessed via myTube. It doesn't download it in mp3/mp4 or whatever file type imaginable. This is to prevent YouTube from banning their access to the YT API I guess.
- When logged in, you'll get an entire page for your subscribed videos.
- Annotation support, Playback speed support
CONS:
- Sometimes the app would take extremely long to buffer a video (Thought it was WiFi problem. Tested opening the vid from Edge, loads perfectly fine).
2) MetroTube
PROS:
- Smooth performance
- Supports background playback
- Download videos or audio of videos for offline playback (the file can only be accessed via myTube. It doesn't download it in mp3/mp4 or whatever file type imaginable. This is to prevent YouTube from banning their access to the YT API I guess.
- When logged in, you'll get an entire page for your subscribed videos
CONS:
- UI is outdated
- Navigation is very tedious compared to myTube (the subscription page mentioned above is not immediately available. You have to tap 'Subscriptions' to get to it.
3) Perfect Tube
PROS:
- Best UI
- Has mini video feature (similar to official YouTube app in Android) where when you play a video, and decide to browse other videos, the video playing will be minimized and continue to play at the bottom of the screen.
- When logged in, you'll get an entire page for your subscribed videos
CONS:
- Performance not as smooth as myTube!
- The performance worsens greatly when using the mini video feature (crashes a lot for me)
- No background play
- No download
- Can adjust color, but can't set it to follow the phone's theme color
- Most of the time, videos won't load after changing the video's progress bar
4) TubeCast
PROS:
- Same as myTube!
- Additionally, it can cast to other devices. I think myTube has this too, but I'm not sure since I've never used it.
- Can be used along with Video360 to open 360 videos. I think there's an app for VR too, and these apps are connected to one another i.e. opening a 360 video on TubeCast launches the Video360 app
CONS:
- Expensive, and each features (Cast, Video360, etc) is available after purchase
- It always loads video successfully, but the loading time is slower than myTube (personal experience)
5) Awesome Tube
PROS:
- Nice UI
- Background playback support
- Download support
CONS:
- Terrible performance
- Often crashes
Note: I used this app when it was fairly new, so I'm not sure about its condition now. Maybe it got better, maybe it hasn't. I'm not that sure.