My bent seems more efficient than my DF on most hills. In my opinion, the circular application of power on the pedal stroke seems to distribute load to all leg-muscle goups more evenly -- I don't get tired as fast, so it's better for long rides. Generally, I climb faster on my bent on all but the steepest hills.
A low BB and tight hip-angle should also improve climbing. I have a European 26/20 SWB with HP-Velotechnik seat and it climbs best when the seat is most upright. My winter project is to extend the seat-bottom so the angle can be increased even more.