I've had good results with the H4n, although I highly recommend to not use the internal mics if possible. Use an external condenser mic if possible, as it will offer a lower noisefloor through the H4n preamps. This is there the Rode NT4 is a good bet because it offers 9v battery powering instead of relying upon the H4n for P48 (which burns through batteries like nobody's business when it's enabled). At a street price of about $400, it's a steal for it's quality and durability.
The issue I have found with the H4n mics is that the electret condensors create a scraping sound with high frequency content such as blade shings, knife sharpening, chains, and other high-frequency content. Running a good external mic into the H4n though solves this problem (meaning it's a mic issue not a preamp issue).
Should you choose to work directly with the H4n by itself, I highly agree with all other responses - you need to be kissing the mic, and do use the windscreen (although a Rycote windjmmer can be bought for about $25 and does a really effective job given that the device isn't using a blimp).
Best of luck!