In this instance I think I'd go with the Piaget.
That particular Breguet is not one of my favorites for a variety of basically subjective reasons and, while that Piaget is not quite at the top of my list either, I think it's a more throughly integrated design overall and a pretty classy piece (certainly more so to non-watch-folks though in all likelihood!).
The Breguet is overly busy IMHO. It has too many conflicting and contrasting displays and guilloche patterns and doesn't really "come together" to my eye. It's too big to be a true dress watch too.
Functionally/conceptually (as if it makes sense to put those two together!), I have a problem with the minute hand on the alarm indicator as well. It gives one the illusion that the alarm can be set exactly to the minute that one wants it to go off, and this is simply not the case. It is only accurate to within a 3-5 minute window, just like basically all other mechanical alarm watches. Because of that, it makes much more sense to just leave off the minute hand (and the needless complexity of it) and have the alarm time indicated by an hour hand only (like most alarm watches). I know, it wouldn't look as fancy or original, but it would be more honest about what it's capable of IMHO.
The Piaget Polo is a very distinctive and well thought out design that is entirely consistent with itself and I find that pretty appealing. My favorite is probably the white gold with meterorite dial.
I don't know anything about the movement in the Piaget Polo (except that I believe it is their in-house automatic Cal. 504P), but I think it's probably a pretty safe bet as far as everyday reliability and timekeeping are concerned. Of course these are both luxury piece by most standards and will have a luxury pricetag attached to service as well.
_john