About a year ago I started using Spotify as my main music provider, last month I also got a Premium account and have been using Spotify in my phone, at work, and at home. A couple of weeks a go I was pointed to Grooveshark, which is a very interesting competitor to Spotify. So I decided to write a little review of both services, and a bit about the other services available.
Spotify is a Swedish service offering ad-based free listening, or ad-free listening at a monthly cost of ~10€ (so called Premium accounts). The service has gotten quite a lot of media attention (at least in the countries where it is available) and has a steady growing base of users (both free and premium users).
The first time a users listens to a track it is streamed and cached in encrypted files locally, minimizing data transfer for often played tunes.
The Spotify client is available for Windows, Mac OS X, iPhone, and Android and Symbian S60 making it Spotify an all-round service. The mobile clients are only available for Premium users though. Premium customers also have the ability to create offline playlists making music available when no Internet connection is available. This is of significant importance in the case of mobile users since users are given the option of creating offline playlists when having access to wifi etc. and playing these at later points in time, when no fast or free data connections are available.
The desktop client is an iTunes like interface with simple and straight forward menus. Searching is easy and offers such options as label search ("label:kitsune"). There is no explicit recommendation service, although similar artists are easily found through the artist profile boxes. Spotify offers no native Linux-client, but the Windows-client runs on Linux through Wine. Additionally there is an unofficial Open Source client, despotify, which runs on most operating systems. Spotify themselves have not commented on despotify, though they have disabled listening to Spotify through despotify for free accounts.
Spotify's library is quite large and it has partnered up with many of the large labels.
One of the biggest drawbacks of Spotify is that it is not available globally, only a limited number of countries have the service. According to Spotify they are expanding, though it seems the expansion has stagnated the last couple of months (it has even shrunk since some countries have been blocked for both Premium and Free customers recently).
Grooveshark is for music what Youtube is for videos. Anyone can upload music to Grooveshark, although users who have uploaded illegal content will have their accounts disabled after two attempts.
The service does not require users to register, and seems to be available globally. The interface is built with ActionScript and will work in most (dekstop) browsers. Searching is available based on the usual features (artist, album, title) etc.
The ease of use of Grooveshark is one of its biggest advantages since it does not require registration or installation of a client. The only thing one needs to do is point their browser to listen.grooveshark.com and start listening. It does not get simpler than this.
The library of Grooveshark is smaller than Spotify's, but most popular music is available. Even artists such as Metallica, who are not available on Spotify,a re available on Grooveshark.
Registered users have the ability to follow other users and rate songs on a like/dislike-scale. The ratings can then be used to retrieve recommendations from the Grooveshark interface through a service called Grooveshark Radio.
Some criticism has been raised towards the legality and copyright infringement issues involved, though as of October 2009 Grooveshark has struck a licensing deal with EMI, thus settling some of the issues.
Last.fm is probably the most well known online music-listening service. Last.fm offers a lot of information about the artists, any upcoming events (tour-dates etc.) and recommends (or just plays) music by artists that should be interesting based on your taste.
I am not a big user of Last-fm's services, but I have tried both the browser-based version as well as the mobile (Android) client. The browser version of Last.fm does not provide the feeling you get when using Grooveshark for instance, as in the website actually being an application.
The Android-client does not provide offline functionality which is a big drawback as it drains battery and adds to your bill (if you don't have a data-flatrate contract). Personally I prefer the Spotify-client, although I am not a great fan of it either.
What I use Last.fm for is finding similar music, and looking up tour-dates and events. It is a simple way to find similar artists, but listening-wise I prefer other services.
Pandora is probably a great service, the crappy thing about it is it's unavailability everywhere except the US.
There are of course ways to get around the geographical boundaries imposed by Pandora.
The recommendations given by Pandora are really good, what I lack though is the freedom given by above mentioned services (unlimited track-skipping, etc). Pandora's interface is web-based, and as far as I know there is no mobile client.
A drawback of Pandora is the un-inspiring site-design, with minimal graphics and very dull colors. Even if Pandora would be freely accessible here, I doubt I would be a frequent user.