I used Apple Music for a year (I think) it’s very good if you have an Apple Device because of the way it integrates into the normal Music App – I hate multiple apps for the same thing.
Library size is a bit of a red herring in my experience, if it’s a mainstream it’ll be there, even if your chosen artist refuses to play ball with them, it doesn’t matter. For example for a bit one of the US Teen Pop stars was kicking up a fuss, Dead Eyes Swift or Big Boobs Perry I forget which, Son was gutted – but all their songs are there, but you might have to put up with compilation CD art work, if you like some weird and wonderful shit, it probably won’t be on any of them.
Anyway, I used Apple for a year because I only stream via my iPhone or my PC, I also have Apple TV but I don’t use it for that. After a year Son had an Xbox and some of the games let you stream your music to listen to whilst you’re playing – but only via their Groove Service, they gave me a 2 week trial, which I pretty much ignored, then a 1 month trial which I used and finally a 4 month trail which I’m using now – I like the fact they have a dark and moody mostly black and white interface and use old library pics of the band instead of album art, but for the most part – who can tell the difference? It’s the same music. I might go back to Apple when the trial is up, or swan off to another one for a few months free.