I've heard this info here and there on twitter and today Eric Sloof again came with the info. The ESX 4 Red Hat linux console will dissapear in the near future. So the only Hypervizor will become the ESXi 4. What you will lose? I did not digg deep enough in the ESXi 4 yet (just installed as a free registered version in my lab and configured with Openfiler), but I know that you do not have the possibility to access your ESXi 4 Server via a Web browser…
If this is the only think I'm loosing, it's ok for me…. On the other side I know that the ESXi 4 hypervizor is easy to install and configure. You can even install it on your USB pen drive and boot up your Laptop/desktop (if compatible).You can test it inside of VMware Workstation 6.5 as a VM too.
Another difference is that ESXi does not support SNMP 'get' method.