I've been reading this forum for a while, but only registered today.
Last week, I finally received the two Kwikset Z-Wave locks I had preordered back in May. I had previously purchased Schlage's competing locks, and returned them due to the unattractiveness and huge size of the exterior assembly, the weak 4-digit codes, and--most importantly--the fact that the deadbolt had to be worked by hand.
After installing the Kwikset locks last weekend, I can honestly say that they beat the Schlage locks in every way that matters. The exterior assembly is small and pretty, the tapered deadbolt works beautifully, the setting DIP switch on the back is awesomely geeky, and the motorized deadbolt is extremely convenient.
Reading reviews on the non-Z-Wave version of these locks, it's pretty clear that many people dislike the plastic back cover, but does it really matter? The finish matches the metal exactly, so you can't tell the difference unless you touch it, and it probably helps Z-Wave signal strength. As for the motor being a little loud, I guess you could say that, but I personally like some audible feedback of what's going on mechanically. And sure, the interior assembly is huge, but so is the Schlage's.
I don't have a proper Z-Wave network at the moment (I'm still trying to decide between Vera, HomeSeer and such), so I haven't tried the home automation features yet. But as far as build quality and mechanical functionality are concerned, these locks are just plain awesome.