I'm still getting to know my 112 -- I've only had it out a few times. I did own a 66, but I never had the two side-by-side. Someone like Dirt Poor Robbins, who's got a bunch of the cabs and gigs them regularly, would be able to offer you more informed feedback. For what it's worth, though, standing right on top of the cab on stage, I can hear the 112 a little better. It's taller and the tweeter and two of the mids are firing at an upward angle. Angling the 66 back might have obviated this, but I never tried it.
I haven't noticed any shortcomings in the 112's dispersion. I had it next to my 2x12" cab the other night. The 2x12" has vertically stacked drivers, with a 6.5" mid. Playing that cab next to a 4x10", I've noticed that the sound is noticeably more even off-axis. I walked around the house a bit while my friend played and the 112 sounded more consistent yet, off-axis, than the 2x12". The 66 might have taken that a step further -- I remember walking around the house several times with that cab while others played and feeling like the sound was everywhere, but, as I said, I haven't had as much time with the 112 yet and am still getting used to it, so I can't say for sure.
On-stage -- I assume re. bandmates hearing the bass clearly, the 66 was great in this regard. Played without any bass in the monitors a few times with no problem. Drummers remarked on this more than once. The soundman consented to leaving me out of the PA the other night, but insisted on keeping me in the monitors, so I can't offer a comparison yet on that ground.