I used to have an emusic subscription and since I canceled that I really can't see signing up for one again. When I first bought into emusic you could download every album you ever purchased through emusic again over and over, which was the main feature I was paying for really. Then they changed the terms of service and made it so that you had to pay for the record again if you wanted to download it again. In short, no matter what the terms of service are now, the people at Spotify will no doubt arbitrarily change them to massively disadvantage you once you are hooked. That's why I almost never sign up for internet subscription services of any kind. For example, I am loathe to upload anything into Dropbox, even though I still have my account, because I am sure one day they are just going to start charging per download to access the content I already uploaded or something weird like that. There's nothing you can do other than walk away from your data when you start using cloud based services if you end up not being satisfied with the service.
Experience taught me that all such services on the internet are really just operating like those rat traps where the rodent can crawl into an opening very easily but they cannot crawl back out. In this case the record industry is basically trying to find ways to make everyone buy their music collection again: I already own records, tapes, cds, mp3s and now I will pay for a music subscription that will pretty much just give me the same music all over again? Its a treadmill for generating revenue.