Most important new features in vSphere 5.1

I was going over the "What's new in vSphere 5.1" sheet and wanted to point out the, from an operational standpoint, what is the most important changes.

1. Improved vMotion which lets you vMotion even without having shared storage (vMotion+svMotion). This is described in this post. For customer transition projects, this can probably come in handy.
2. vSphere web client: This is now the default interface for managing vSphere - it will probably take a little getting used to for the server admins.
3. Zero-downtime upgrade for VMware tools: Not having to reboot the VMs after tools upgrade is a big step forward (as an IT service provider, it can be close to impossible getting a maintenance window for all your VMs)
4. Larger VMs - up to 64 vCPUs (you will have to have sufficient underlying hardware though, so unfortunately it can't be simulated in the home lab :))
5. Virtual hardware v9. Upgrading will require VM downtime. One can only hope that, in future releases,  vHW upgrades can be done in-place.