On the Aquia:
They are ALL 1.6gpf/.9gpf Dual Flush, Elongated, Skirted, 12" rough-in (except where noted)
CST412MF: Universal Height, 2-piece
CST412MF.10: Same as above, with a 10" rough-in
CST416M ("Aquia II"): NOT Universal Height, 2-piece
MS654114MF: Universal Height, One-Piece, comes with SS114 Seat included
All the Aquias are popular, reliable toilets, on which Terry has had less than a 1 percent return rate after selling thousands of them, and people come back for more. In short, most people who choose to buy a dual-flush and who buy an Aquia like it very much.
I would say get the toilet that you want, rather than the supplier that you want.