Looking for thoughts on Proxmox VE intallation re-do/ upgrade

Hi all,

I had a previous admin turn unresponsive about half way through a proxmox installation. Fairly small/ basic configuration that used Proxmox VE 2.2 hosting two wordpress sites and one vbulletin site using four nodes.

The cluster was based on Proxmox VE 2.2. Since the web nodes are only running on three of the nodes (and one wordpress installation is seldom used) I updated the two relatively unused nodes to Proxmox VE 2.3 already. Just to level-set here is the current configuration:

Configurations
Here is what the current configuration looks like:
Chassis 1
Node 1 - Local SSD + Local HD (Proxmox VE 2.2) running wordpress on CentOS 6.3
Node 2 - Local SSD (Proxmox VE 2.3)
Chassis 2
Node 3 - Local SSD + Local HD (Proxmox VE 2.2) running vBulletin on CentOS 6.3
Node 4 - Local SSD (Proxmox VE 2.3) running lightly used wordpress

The web nodes are installed onto the local SSD storage. So I know that when the Proxmox VE 2.2 nodes are upgraded I cannot live migrate while I reboot the nodes.

Here is what I am trying to do
1. Upgrade all four nodes to Proxmox VE 3.1
2. Have the two hard drives act as a backup destination for the VMs
3. Have the wordpress and vbulletin nodes moved to HA

My main question is whether I am trying to do too much? I am certainly not a great admin (had hired someone else to be but that has me stuck) and the big question for me right now is whether I should stick with Proxmox or swap to ESXi or Hyper-V which I am familiar with. Since I do have two "free" nodes I have enough room to do a swap fairly easily. Both the main WP and vBulletin will run fine on a single node if need be during a cut over.