I've mostly used the free VMware server and player, but thought the networking support was about the same as Virtualbox. What have you found that is significantly different? So far I mostly prefer VMware server for the ability to run the console and disconnect/reconnect where with virtualbox you seem to have to decide ahead of time if you want a console or not - but I'm not a big fan of the new web console in the 2.x series.
There are two major issues I've had with VMWare Workstation that have not occurred in VirtualBox:
1) When the host network connection comes and goes (either intentionally or otherwise) the networking to and from VMWare VMs fail completely and cannot be restored without a host reboot.
2) DHCP via an external system (router/gateway) often fails to the VMs with nothing more than timeout errors in the VM logs.
VirtualBox has issues to, as does most software, so I end up using both to get all of my testing and simulations done.
-geoff
--------------------------------- Geoff Galitz Blankenheim NRW, Germany http://www.galitz.org/ http://german-way.com/blog/