I've always used VBox, since it was introduced by the original developers. (We all know that Oracle did not develop VBox, right?)
I've seldom had problems of any kind with it. This past couple weeks, after purchasing an actual server board, I've had problems with Vbox and USB mouse. Among my attempts to solve that problem, I downloaded and tried the latest and greatest VMWare. Found that I had the same problems. After reading some obscure posts on the matter, I ended up using a PS2 mouse, and the problems disappeared.
Note that one of my primary reasons for getting this monster of a server board, is A: the CPU's support virtualization and B: the board supports LOTS of memory so that I don't have to starve the VM's for memory.
I am, right now, running three VM's with two gig of memory each, not to mention that I've created a two gig RAM drive for system caching, and I'm STILL only using 25% of my memory.
So, VirtualBox, all the way for me.