I find it interesting that the majority of reviews for the DI20 are bad. My experience has been great (knock on wood). I have 4 of them. For the price, I don't think I could ask for a better deal. I certainly prefer it to passive DI's in the same price range. I have only used these in live (sound reinforcement) situations.
Two things to keep in mind:
1) make sure your board's phantom power supply is adequate to handle everything you are running; mics,DI's, etc... can add up to a substantial current draw, relatively speaking. The DI20 spec sheet says it will work with 18 to 48volt. I have only run it at 48 volts from a Yamaha analog board. If your supply is overloaded and browning-out, it may create noise problems.
2) Be careful with the attenuation switch. I have run several different types of acoustic guitars thru this DI and haven't had any problems. However, all guitar outputs are not created equal. Use 0dB if you can get away with it but if you get even a hint of distortion during sound-check, insert the 20dB pad.