I purchased Rock Band for myself on release. I've been playing it pretty regularly for over a month at this point. The bundle I purchased contained a guitar, a drum kit, a microphone, a usb hub to plug them all into, and the game. Everything seemed to work fine out of the box.
Rock Band comes with a very nice variety of songs on the initial game disk. There are 58 total playable tracks with 45 of these being featured in the main set list and being generally by well known artists and 13 being "bonus tracks" which are by less popular or independent artists. Of those 58 tracks, 51 of them are actual master recordings as opposed to covers which is an extremely high percentage in this genre. In addition to this, every week since the game has released at least 3 more songs have become available for download/purchase (at lower prices then we've previously seen in this genre) for those that want to expand their collection of playable tracks. To date I have purchases and enjoyed all of them.
There is a solo tour mode available with this game which is fun in and of itself and great for practice, however the game really excels when you use it to play with multiple people like it was designed for. Over the holidays I had the opportunity to play this game with the "Full Band Experience" and it was out of this world fun. At various times, myself, my fiance, my brother, my step-dad and my mom were all playing together and having a blast. This is especially significant when you consider that my parents are not at all familiar with gaming in any way and they were still able to take part and have a lot of fun.
One important caveat must be mentioned and that is the initial instruments that shipped with this game seem to be more prone to breakage/malfunction then should be warranted in a new product. I myself have had to send in my guitar AND my drums for replacement at this point. On the bright side, they have the best product replacement plan I've ever seen to date and the amount of hassle this creates is pretty much non-existant.