Guitar Hero World Tour is a great game, especially if you've not played guitar hero or any other rythym game, this would be a great place to start. There are 86 songs, with downloadable content to released every week. The gameplay for guitar is the same as the previous games, but the bass has a new open string feature, where you just strum without pressing any buttons, this makes bass as interesting as guitar in my opinion, and gives it a bit more diffuculty. The drums are comparable to rock bands, but they have a extra note if your're using the guitar hero drum kit. The vocals are basically the same as rock band, and very similar to many karioke games out there.
The difficulty is easier than guitar hero 3, but harder than rock band 1. The only flaws with the game, are the GH tunes sounding like a ring tone on a mobile phone, and the online quickplay is lucklustre and somewhat rushed. Overall a great game however.