Have had this product for about 6 months now. First the good:
Records audio excellenty through the built in mics, easy to adjust setting using the High, Medium Low sensitivity setting to suit recording acoustically in your bedroom to full band in cramped rehersal room. Quality is excellent and it's easy to record just press the big red button twice and you're away
Can act as a 4 track recorder, Further more you can take tracks you have recorded in the song mode and use them as a starting track(s) for your 4 track composition. This is a useful tool if you get an idea quickly bung it down and then want to later try adding to it e.g. maybe some bass or a backing vocal etc.
Variety of inout sources allowed from in-built mics to electric guitar input to condenser mics (unit will supply phatom power).
Works as a USB storage device for your PC really well just plug the USB cable in open up the H4 folder and copy and paste files where you want. Will record directly to Mp3 so it's a really quick way to get ideas/recordings of songs up onto My Space etc.
Now the bad:
It's fiddly. It's not that bad in general but to give an example. The unit comes with in-built effects and if you want you can edit the presets or make your own up. The trouble is you probably won't bother doing this as it's just all a bit time consuming due to the nature of the controls.
You'll also occasionally find yourself pressing the wrong button and exiting a scren un-intentionally. It's not anything you can't live with but it will maybe put you off using some features.
Audio Interface for PC recording. This is the main fault with this unit. Tried to get this to work properly for ages and just couldn't get a decent recording. There was always a big latency (delay) creeping in. Even when I used direct monitoring found that the supplied Cubase Le4 s/w was recording it not in time to the tempo of the song i.e. off beat. I really persevered with this updating drivers etc. Eventually after several months took the decision to buy a POD Studio UX2 interface (other interfaces are available) and lo and behold worked perfectly first time.
So if you're choosing this unit over another unit based on the audio interface capabilities, well, I wouldn't.
HTH