Summary: it doesn't work with Windows 7. Drivers won't load. Tech support is non-existent. All they said was updates will be released "someday". Take a pass on this product. I'll be returning mine and probably won't be buying anything from M-Audio again given this experience.
Summary: I am using this product both to learn how to play piano and to compose music. It is easy to use, inexpensive, and a solid piece of equipment. If you simply want a keyboard to connect to your computer, I would recommend the KeyRig rather than the KeyStudio, as it is less expensive, but if you ever want to play live or record a guitar or microphone the KeyStudio is the way to go.
Pros: Easy to Use, Portable, Realistic Sound, Responsive / Good Action, Touch Sensitive Keys
Cons: Limited Sound Selection, No Speakers, Plastic Feel
Summary: There are two kinds of uses for this controller. One is for someone who wants an inexpensive, portable piano to practise or teach with. The other is someone who is an amateur and wants to "fool around" making recordings or compositions. Both are likely to be disappointed. This works as a stand-alone digital piano. If you plug in a 9v power supply (not included) and a pair of headphones, you can use this without connecting it to a computer at all.
Summary: M-Audio has done a great job with this product. I was interested in getting a USB music keyboard to use with my music software.(Sequel 2) At the same time I was looking into purchasing a USB interface to record bass, guitar and vocals. Then I found this keyboard and it does it all! (At a very good price by the way.) I'm kinda old school regarding midi products. I've had all the rack gear, sequencers, etc. and this is my first dive into software based recording.
Pros: Easy to Use, Portable, Realistic Sound, Responsive / Good Action
Summary: Having bought the KeyStudio 49i a year ago with the intention of building a home studio, I now realise that this was a poor decision. I decided to buy the KeyStudio as it had an integrated audio interface and I could therefore record my guitar and start to produce my own songs. This was great from an amateur's point of view, but as my musical knowledge increased I soon realised that this keyboard was a poor alternative to a separate MIDI keyboard and a separate audio...