For what's it's worth, I'm running both C4's and 393/91's in the field into an R4 lately, and I think I seriously like the C4's better when it's card vs. card. Also, having the omnis can be really nice at times (acoustic j-disc action can't be beat), but so can having the 93's for boomy back-of-teh-room venues. Thing is, I've been running 4-channels a lot, so that skews my thoughts on this (if you can run 4-channels, then owning 4 mics is better than owning just two). But if you're running only two-channels, you might be better off with a pair of cards and a pair of hypers. Tough call...