I think I would only use spotlight for contacts and because of that I use voice control more. Especially if the rumors are true about voice control working through bluetooth headsets, then I'm all set!
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.
I use it religiously! My home page is exactly how Apple sets it up and the rest of my apps are in alphabetical order because that's how iTunes syncs them over. I use spotlight search for everything. I love it.
I don't. I find it to be an annoyance. It's like an unneeded (for me) feature that just gets in the way sometimes. I only have 4 pages of apps and they're organized very well. I know were everything is. It's easier to just swipe and find them as opposed to typing it in. I wish you could disable it