I have that recorder as my keep in the bag at all times recorder - just in case. I gotta say I really do like it.
The reason I bought was for the multi-track recording and the M/S decoder. I thought I would use it as a travel recorder with my Sennheiser MKH418s (M/S), but turns out that I only ever use the on-board mics. Reason being is that if I'm gonna be bringing my other mic with the softie or windshield and all, then I might as well bring my Sound Devices. I used to only have a Fostex FR2 recorder, wich was very big to travel with, so this made sense.
I haven't even yet tested the XLR inputs, but from I hear they are pretty noisy. The on-board mics aren't very noisy at all. I think that sound pretty damn good actually. I also like that you can choose 90 or 120 deg for your stereo image.
If I had to do it again though, I would buy The Sony PCM D50. Because from what I hear it is even better sounding, and considering I never plug in other mics, then that recorder would be more suitable.
If you wanna hear some recordings from the H4n, there are a few from my holiday that I will be postingposted on {sound + design} very soon{sound + design}. Otherwise you can listen to some older ones recorded on it.
Hope this helps a little.