I have been a paying user of WMware personally since the beginning and I have worked on their enterprise stack for several years. With the changes being made I cant see myself wanting to spend any personal money on it I and I would not recommend someone to start fresh with it, but for a lot of enterprises, they will, short term, have little choice than to pay the fees.
I have no idea about the state of Microsoft HyperV. The little I have worked with it, and that was quite a few years ago now it seemed severely lacking in the tools department.
Oracle owns VirtualBox, and even if they started to build it out (or have they?) going to Oracle to avoid high fees is not going to be a good idea.