I enjoy making video clips of bands that I like.
The Zoom H4N and I believe most of that family of handy recorders won't accept professional line level, only the lower consumer line level. I would certainly check this one before contemplating it. Carrying extra attenuators, etc when taking sound from a desk is a pain!
I made one of these up in 1983 as a way of recording a course and questions on different channels onto tape. http://permacultureplants.net/Audio/pdc83.htm
Be aware that the two sources (typically microphones) need to be reasonably well matched in output sound, or go through preamps. I was lucky that the old AKG lapel was closely matched to the Audiotech shotgun. Some mic combinations just didn't offer sufficient volume without clipping the other's audio.
I have had the H4n for many years now and the H4 before it. I have found a major limitation with it is line input. I use it to record sound straight from the desk at music festivals I am filming. Sadly what zoom considers line level is consumer line level not professional line level which is 4db louder. The net result is that the audio is clipped and becomes unusable. I have worked around this by using a "SM Pro Audio DJDI DI Box w/ Level Attenuation" which is an awesome piece of kit that has other benefits as well like Continuously Variable Input Attenuator (you can even take a feed straight from the speaker cable!) and Ground Isolation Switch and cost me about Aus$35. It is another piece of gear that you have to drag along though and if I were looking today pro line input would certainly be a deciding factor.
Most sound engineers whose desks I plug into know the H4n and speak highly of it.
Having the 2 tracks straight from "front of house" is great and sometimes I also record 4 track the other 2 straight from the H4n mics for an audience mic. Camera mics also contribute but it's great to be spoiled for choice:)