I have had no issues with having my main monitor to the left or to the right. I have a laptop and at home my external monitor is to the right while at work it's

I have had no issues with having my main monitor to the left or to the right. I have a laptop and at home my external monitor is to the right while at work it's to the left; KDE handles either version perfectly. The "hot" corners move to the extremes, as appropriate, and everything else works well too. In fact, over all, KDE has been the best system for multiple monitors I've used (choosing from several versions of Windows, OS X, Unity and Gnome 2).