This thread got me to install Spotify last week. The free version has limited skips (if memory serves 6 per hour) and the ads are few and 30 seconds long (with no ads in succession). I like that I can pick Judas Priest and listen to just them for hours.
For me streaming won't replace digital downloads. I still enjoy listening to live bootlegs and albums from front to back. And with digital downloads I can create my own playlists in Plex where I rarely skip a track and can stream to multiple devices wherever I am in the house (and could do it remotely if I really wanted to). And Plex is available on all my devices where Spotify is not.