http://victoryroad.net/album.php?albumid=509
By the way, these waveform pictures? It's actually generated from a Game Boy game. The Game Boy's PSG isn't as simplistic as the NES'.
Let me see...
The NES can only do mono output out of the box, while the GB can do hard L/C/R, per channel.
The NES has five channels - 2 square/pulse, 1 triangle, 1 pseudorandom noise, 1 DPCM. The GB, on the other hand, had 2 square/pulse/sine (can be swapped in the middle of a waveform, like the images shown), 1 does anything except can't be used as a PCM instrument channel (triangle, check, sine, check, square, check, extra harmonics, check, limited FM, check, 4-bit PCM (one-shot), check...), yet another pseudorandom noise channel, and that's it.
The GB was certainly more flexible, given that we have to stick to stock hardware. However, the Famicom's sound was expandable. We know how that went.