According to the specs in the catalog, the swallow is:
Width 153 mm (as compared to 152 for Swift)
Length 287 (as compared to 280 for Swift)
Wt. 360 g (as compared to 370 g for Swift)
When I weighed my saddle, it weighed in at 354g.
The Swallow seems to be a little flatter across the back than the Team Pro that I tried. (bmike would be able to tell you for sure about that). I've not tried the Swift, so I can't tell you about that.
For me, the flatness across the top makes it feel wider, and my sit bones are not "falling off the edge" when I sit up. However, the saddle was intended to be ridden in the more agressive aero position. It is quite comfortable in that position.
The rails on the Swallow are longer, which I really like! It gives more fore/aft adjustability - especially aft.
The ti frame seems to be a little flexi and absorbs shock (but not so much that you compormise power transfer).