I've been running UNR on my eee 1000 pretty much since it came out over a year ago (I was using easy-peasy before that), but I'm curious about the new Kubuntu netbook edition. Ultimately, KDE is better looking, and has some really friendly software, but I'm worried about performance - that display has got to be a processor hog (and by association, battery!), no?
How much does Kubuntu netbook edition impact battery life?
Kubuntu Netbook Edition, running on my Asus eeePC 1000H is flat out unusable. The interface is so slow, I can sit and wait for 30 seconds for a button to press, or the task switcher to come up. I've switched off all graphic enhancements, and I still can't see me using this thing. Makes the whole battery issue moot. Next up: Jolicloud!
The battery life should be relatively the same for each of them. Sure there will be a difference but it will be negligible.
The bigger issue here, I think, is your concern over the importance of battery life.
Which is more valuable:
I suggest LUbuntu, it is a lighter OS so will allow your CPU to run slower, this adds up to longer battery life :)