I've always liked 2-register chronographs; the bilateral symmetry is pleasing to my eye. And yet you're not alone in preferring 3 regs - the happy result for Eric of course is that the outlay is correspondingly less.

I get Chuck's point about functionality, but from a purely aesthetic perspective I tend to prefer 2 to 3 where registers are concerned. With some exceptions, mind - for me, a triple calendar needs an hour register as counterpoint to the day and month windows. A 2 reg triple calendar could look unbalanced.