I have a 112 and 2x115's.
My reasoning for the three was that it is easier for me to get mid punchy with any of their cabs with a choice of bass and EQ, but not so much a full old school woolly thump with just a 112 or a 115, 112 stack. I've never been a fan of 10's so the 2x10 never concerned me. Regardless. If you are playing to 300 to 500 folks, the 112 and 115 are going to melt the walls if you jack the volume anyway.
I'm still glad I purchased both sizes and the additional 115.
After the fact, I prefer the 2 115's. If the physical room properties are a concern, I'll use the 112 and 115.
Mesa is quality stuff.
EDIT. There is truth to the statement you may have read concerning the 2x115 versus only one 115. The tone definitely "Blooms". Very full and thick and still articulate.