Your post prompted me to give it another try. I found that you can drag windows between workspaces in the "mini workspace viewer" in the upper right, which is definitely an improvement over Ubuntu. However, you can't move them by simply pressing the windows against the side of the screen.
The focus stealing issues are the same as in Ubuntu. Start launching an app and switch to another window; the app will jump in front when it's done launching. Argh!
However, I prefer to re-map CapsLock to <Hyper>, and define <SHIFT>-<HYPER>-Up to move window to workspace up, and so on.
Can't help with the stealing, sorry.
Anyways thanks for the tip.
In common it seems with most features of the UI KDE has a setting for that!
It's in the settings with the "focus policy" slider (click at one end, hover at the other) labelled as "focus stealing prevention". IIRC it was in KDE3 too.