I stopped using it a while ago because the app kept crashing on my phone , now I just pay $8 for a google music premium and still gets to upload my own library .
i use it to turn ugly illegally downloaded files into pretty high quality files, but that's it. all the other services it provides are crap and fail all the ****ing time
1. It saves your WHOLE library on iTunes, and any device you sync on with your Apple account it downloads your whole library to it. When I got a new Laptop I didn't have to transfer any music myself, except for files I never put in iTunes.
2. It keeps the songs in a Cloud, so on devices such as an iPhone it takes 0. The song only takes space when you download it, but on Cloud you can play without downloading. You just need Wifi, I think. I have like 1,200 songs and only downloaded 10 and have the whole library. It's great for me since I use Spotify most of the time, so having music taking up most of my space would be <<<
3. If you downloaded (for y'all cheap ones ) it gets the covers, album title, etc and makes it all neat like you bought it.