I'm confused on the 120's. Which has the biggest *usable* IC? I know what the specs say, but I have heard that the Schneider 121 actually covers quite a bit more than spec and quite a bit more than its 120 replacement. I'm then curious about performance, because I've also heard the SA 121 isn't nearly as good a performer resolution-wise as the SA 120. Also, I'd be curious to know falloff characteristics for these.