As a listener I love spotify and most of my music comes from spotify. I have also collection of CD`s and couple of donations/bought digital copies but mostly i prefer streaming + donations.
My love for spotify is becouse of couple of reasons:
1) I have it on my phone, laptop, ipad and i have all my liked, stared files, list of all artists that i follow, the news feed about updates from them.
2) Related artists (maybe not always the best) helped me discover awesome music based on fact that have known FSOL and Peace Orchestra (yeah, i ended up with psybient based on those 2 + Astral Projection:))
3) Start radio from - also awesome for creating random playlists of tunes from specific genres and styles (its doing preaty good job of guesing tracks based on thumbs up/down feedback in player).
4) Offline mode and saving localy files.
5) links to web player or spotify player - i ofter talk to my friend on skype/gtalk about music and our inspirations and stuff like that and easy pointing to track is awesome.
I hope that spotify will grow and one thing that i would love to have in spotify is the ability to go outside spotify (links to home pages) and option to donate to artist in spotify. Other thing is that for me the 10 $ (in poland it is even cheaper) is a joke for high quality streaming and i would be able to pay around 20$ for this service monthly just becouse i`m so happy about it.
One other thing that is missing is the ability to have flac or other loosless compresion for offline mode/saving playlists but i can understand why at least for now they dont have this option implemented.
From the "producer" point of view, i actualy dont know becouse i`m just starting my journey, and i will probably never "live of music", as I`m software developer and music is my hobby but becouse of lack of time i wont probably achive anything money worth. One thing i know that both me and some of my friends found artists on spotify and then bought physical copies of albums or donated to artists so besides revenue from streaming there is a promotion aspect that is very important and people should not ignore it (thats only my opinio of course).