Since i own a Pre for now along with iphone 3gs, i use U-search a lot. Flip open KB, start typing, phone number pops up.
On the iphone, i can't say i'm using spotlight in that manner. Not that spotlight isn't great for it but because its not as easy or quick to start using as the Pre's is. Probably because of the KB. On the iphone, I've used voice control or go to phone app and hit favorites or recent calls. It just depends if the person i'm calling isn't already in favorites.
If i tried to use the Pre in the way i use the iphone, it'd be slow going. The Pre phone app is crap. Scrolling through contacts (that takes long to open) that has facebook mixed in would be even slower.