I can respect that opinion but I look at it this way. Yes, Zwave does have the advantage that (at least in theory, and mostly in practice) all manufacturers products are interoperable. So, you can build a standalone ZWave network with devices that communicate with each other. And yes, there are alot of choices. But, there are issues too. There are several different hardware devices (some locks come to mind) that don't play nice in a 'standard' ZWave network. So, while interoperability may be the norm, it is not guaranteed (like you have between all the UPB manufacturers). There are many manufacturers of Zigbee based lighting including Crestron, Centralite, Control4 and Colorado Vnet. They all have their separate implementations.
Steve - I agree with your take also. All technologies have their pro's and con's.
While ZWave is limited to 232 nodes and Zigbee is theoretically 65K nodes, the Zigbee Stack as continued to bloat even further from the first stack. Our first stack used around 40K of FLASH memory, Zigbee Pro is now 112K and this does not even include the AMI (metering) profile. The problem I see with Zigbee is there is so much in-fighting of what should be or not be in the stack that they never get anything done. This is why you have so many products that are interoperable.
You mention the lock issue with the Schlage Link, Schlage tries to lock people in with having to use their bridge. This is not the case though, MiCasaVerde already has support for the Schlage Link in Vera. I have it installed in my house and when I open the door lock, Vera turns on the light in my foyer.