The first annoyance was that it didn't seem to work correctly with kwalletmanager. It usually didn't retrieve passwords, but the behavior was unpredictable. I decided to try whacking the config for both programs:
killall knetworkmanager kwalletmanager
mv ~/.kde/share/apps/kwallet/kdewallet.kwl ~
mv ~/.kde/share/config/knetworkmanagerrc ~
After that I only had to enter the network password once and it has since been saved/retrieved without issues.
Second annoyance--I usually hibernate whenever I dock/undock, but there are times when I'm forced to actually shut down. It's after a real shutdown that knetworkmanager misbehaves. The message is "No network device found" and it persists until 2-3 hibernates later. Until it decides to cooperate I can use iwconfig, wpasupplicant, and dhclient just fine on the interface. I've tried killing knetworkmanager and the backend NetworkManager processes, but the bugger won't see my network interfaces until I hibernate a few times. And no, Google doesn't have an answer yet.