I finally got round to giving Spotify a try this week, purchasing a one month 'Premium' subscription - for €9.99 or approx $12 (which will be automatically extended unless I cancel my subscription). It's free in some European countries, though you will have to put up with the occasional ad with the free version. Unfortunately our friends in the US will have to wait a bit longer, as it's not yet available there.
Once opened, it's much like your regular music player (MediaMonkey/iTunes). It looks similar and has much the same functions. The only difference is that the songs it plays aren't actually on your computer (they're stored in a gigantic supercomputer buried deep in the Arctic, possibly). Other than that, there really is little difference. Like MediaMonkey, it has a handy queue function (titled 'play next' in MediaMonkey).
"It's like a magical version of iTunes in which you've already bought every song in the world" Wired
The main difference between your using your own computer and Spotify is quite simple: the music. i.e. what music does Spotify have and what doesn't it have?
Well, for the casual music fan, Spotify will have more than enough. All the big chart stuff is there, as well as a pretty decent back catalogue of the bigger mainstream bands and acts (i.e. Coldplay, Radiohead, Franz Ferdinand, Bruce Springsteen, Lily Allen, New Order, Blur, Eminem, Madonna, Bob Dylan). While there are some odd omissions in this category, with e.g. U2, the Killers, Rihanna etc missing. This is surely a record label issue, and it's probably just a matter of time before they get on board too. The more momentum Spotify picks up (and users it gets), the more it will surely (be able to) add. iTunes didn't have the amount of songs it now has on day one either. Spotify currently has approx 6 million tracks.
As a true music lover would never want to give up their own collection anyway, Spotify should really be viewed more as a supplement than a replacement. And as supplements go, this is a pretty damn impressive one.
Spotify can be used on any computer that has the software installed, so you can use it while on holiday for example, while they are currently working on making it available to iPhones etc, so you can use it on the go.
They've also developed a built-in Last.fm scrobbler, for all you users out there.
As for negatives, I wish Spotify would have somewhat more information available, e.g. the type of stuff last.fm and your regular music player already provide. Last played, Top played etc. Plus the home page could be just a bit more informative. Maybe even include your own personal charts. Also it would be nice to have a choice of skins.
Spotify is still in its infancy however, so they surely are working on more options and applications.
Overall , I'm a pretty damn happy camper.