I am still in the formative stages of setting up 5 SHO-10's and a 18.T. But I won't let that stop me from posting some strictly subjective thoughts:
Well the other day I wired up the front stage (3 SHO's) and the 18.T and level matched them with the Rat Shack. No EQ yet. Naturally, I had to listen to them even in this preliminary stage. I used Fantasia 2000 on BD. The sound was HUGE and clean at VERY HIGH levels(I'll get more on this later) I used the tin soldier part with the Shostakovich 2nd piano concerto which is very dynamic. I figured this would be even more demanding for actual SQ than the usual exploding stuff movie scene. It was fantastic, it was a very in your face feeling, not in a bad way, more like you are sitting in the middle of a symphony orchestra while they are playing their ass off.
I know the subs are not EQ'd yet and it is possible I could be near a null based on room dimensions but I do want to get a quick impression out there. My Dad formerly had a Infinity BU-2 ported sub. Now going from this to dual 18"s is no comparison, but like many have said it was not the same difference as I expected in my head. His old sub was "boomy" and "rumbly" with any high volume material, whether music or movies. The 18.T does not call attention to itself unless needed and when needed it sends a wave of clean bass over you.
Well after listening to this for like seven minutes my ears were starting to hurt a little. "My God!!" I was thinking "how can people listen at this level for two hours!!!" It turned out that when I was using the Denon pink noise I adjusted the master volume to read -10db to get to reference level, but when I listened to the movie I forgot and put the volume on 0db so I was actually listening at +10db above reference. No wonder the Rat Shack was measuring over 115db peaks.
I did warn you I am still a resident of noobieville.