I'm torn...
I'm getting a new aerobar set and stem, and have narrowed it down to two:
1) Profile Design Carbon X 1.5 (integrated base/aero/stem)
2) Profile Design Cobra "set": T2+ Cobra aero bars, Cobra S Stem and Cobra Wing base bar.

When i do the math, the X 1.5 comes out to be fifteen grams (three nickels) lighter, and about fifteen dollars pricier; in other words, the differences are nominal enough not to make a difference one way or the other.
I've read that the aero bars being mounted on the underside of the base bar of the X 1.5 provides a more aero position, which sounds great (though i've never ridden aerobars mounted that way myself).
Other than that, i can't find a difference. The stem size i'd need if i went with the S Stem is 100mm, which is what the X 1.5's "stem" is.
Adjustability is the same too; i initially figured i'd want to adjust the aerobar width along the base bar, but when you look at the Cobra Wing, you realize that there's not much room for adjustment there either (though you can rotate the **** out of the rests, so that makes up for it).
Other than the obvious numbers (which don't differ), is there an advantage to going with a single piece vs the traditional pieces?