MOG is $10 per month for Premium version and that allows multiple devices, but not streamed at the same time. One at a time. IMO I see no purpose in uploading my music to Google, when MOG has everything in 320kbps. MOG has significant catalog in remastered versions. Very much better sounding. MOG is not available outside USA.
I like Poweramp. I tried Neutron, but it over samples everything to 32 bit. I am one who finds something irritating about over sampling to 32 bit. I do like OS to 24 bit. That is just me, though, and you should try it yourself.
I have a 32G mSDHC and that holds plenty of music. I guess some have 64G cards. You should have no problem storing music. I think a 32G card could store at least 5000 songs, maybe a lot more.
Like cloakn'd I like and use TuneIn and Soundhounds and MusicMatch. I sometimes get in a lyrics viewing mode.
My gripe is that these phones still don't enable USB Hosting. Until they do we can't get the best sound out of them. It is what it is. Still, it is amazing.