vmware and centos makes my day
CentOS6 is the best host. Linux has way better firewall and routing capabilities with route, openvpn and ipsec. I've had all problems with routing when using windows as host. And it is 100% compliant with RHEL so all commercial linux software supports it. It also do not have the dreaded systemd (yet).
I develop commercial software used by banks/processors requiring me to log into their systems via all kinds of vpn software and citrix. I mostly use windows xp as the guest for it. some of the guests have failed when running on a windows host, but never on a linux host.
Our software is cluster based so I have lots of centos5/6 guests with dhcp along with database servers (DB2/Oracle express ) and websphere MQ guests for delivery. I use the express editions because they are compliant with the enterprise editions but I do not have to care about the licensing and lower requirements, so copying vm-images around has never been easier. I keep separate guest-vms for each customer emulating their setup. this way I can build rpms that require just a stop of application, rpm -Uvh new package and start. (usually 20sec) in production.
When it comes to the virtualization I use vmware workstation9, it works fine with the rhel6 kernel and everything works. even hwrendering (I use the binary nvidia drivers on the host) of windows games like skyrim on win7 guests works excellent.
Years ago I used the vmware server v2, and afterwards I was forced to use Xen and virtual box. (didn't want to pay for linux software) they work fine for stuff that do not requite performance. Our software is 25%-50% faster on a vmware guest compared to virtual box guest. So it is a very easy decision to use $179 for a vmware license. vmware handles io _WAY_ better than xen and virtual box.
Personally I love opensuse, but their upgrade policy makes me have to reinstall every time there is a new relase, so I have some opensuse12.3 and 13.1 guests I build and run our software on to make sure it works. with CentOS it is just yum update(ex: to upgrade from 6.4 to 6.5)
and all your binaries still works.
I've created startup scripts which starts my database and websphere MQ guests automatically on reboot. I have a samba share on the host I share among all the guest.
Here I have the source build and release directories and a webserver so I can get hold of all the software nomatter if the guests are down and I'm on a customer vpn guest and need to install software built on an other guest that now is down.
Every guests except the database ones I keep under 20GB in size, that way makes it very easy to backup and move around to other vmware instances like my laptop, home computer or to ESX/vsphere servers. I have base guest images with the base software requirements so designing for a new scenario is just a clone away (with SSD cloning 20GB takes 20sec).
Earlier I used to have several noisy boxes under my desk. they are now all in a single almost silent workstation. I have around 30 different virtual machines where up to 8 running at the same time on a 32GB Intel i74770 512GB SSD with a /shared sata disk of 2TB.