the icon theme is a matter of personal taste - and may be only hurt in $users eyes - the kde-engines, esp. the gtk engines are a little bit different. They can really do harm. So we dropped qtcurve and oxygen long ago after a lot of testing and debugging.
The result may no look so fancy, but works reliable - and $user can change these things to whatever $user want. (Ok - i will never ever support stability problems if qtcurve or oxygen are running - but thats a complete different story)