Having upgraded to OS X Mavericks just recently, one of the main questions for me was, whether I would need to upgrade from VMware Fusion 4 to the current version (which is Fusion 7). Initially the thought had not really occurred to me, but after the second crash of my MacBook I started to look around. The majority of content I found was about the support status and some people had gotten really agitated during the discussion. But little was said about the technical side of things, i.e. whether the stuff was working or not.
What I can say today is that for me VMware Fusion 4.1.4 works nicely and without issues so far. I use it almost exclusively to run a company-provided Java development environment on Windows 7 64 bit. So no 3D graphics, USB drives, or other “fancy” things.
The crashes were most like caused by an old version of the keyboard remapping tool Karabiner (formerly KeyRemap4MacBook). Once I had upgraded to the appropriate version, the crashes were gone.