I have a Dangerous 2bus (LT). I don't think I could go back to just ITB mixing.
Basically, think "space" and "depth", not warmth. A summing mixer's basic job is not tone, but clarity and punch.
By way of example, I'm finding that with all the sonic space the 2bus affords me, I use about 1/3 of the plugins I did before. I don't have to squash things to hell and back, or tweak them beyond recognition for them to be heard in the clutter that is PTHD ITB mixing. Everything has its own little sonic world now that it can exist in peacefully. Basically, it saves sweat.
The added bonus is that once I ran my 192 outs to a patchbay, then to the 2bus, I was able to patch my analog gear back in. Suddenly, my distressors are getting used for something other than tracking. It's SO COOL to have that stuff usable again. Of course the downside to this is that I am eyeing new analog outboard gear like I never have before. Looks like I'm due for a 15th mortgage.
By the way, I'd shoot for the full 16 D/A outs to get the best out of your summing box. I only had 8 at first, but 16 was even better. Naturally, 32 would be better, so would 64, etc, but 16 seems to be the minimum to get your money's worth.
Hope that helps,