I think the three sets are around the same quality really and there's not a great deal in it. Ksyrium Elites are the same kind of level as Ultegra and the same kind of wheel - decent quality, sensible weight, shallow rim with no aero benefit. Some prefer Mavic, some Shimano.
The Fulcrums with their mid-section rims are a slightly different sort of wheel (35mm I think) which is quite nice for everyday riding since compared to shallow rims you feel you get a little bit back from them for your efforts when you push them beyond about 17-18mph. Some say the hubs aren't as reliable as Mavic/Shimano and there's a bit of weight penalty. They're not quite as light as some mid-section wheels, which you might notice on the climbs and when accelerating from a standstill. But my guess is you'll probably find your times are a bit faster on the Fulcrums for anything but a really hilly ride.