Thanks for the comment. I think a lot of people are in the same boat you are. VMware HA is one option you can explore, but as you say there is downtime associated with that. The reason being that HA is relying on the heartbeat between the VMware Tools and the host. If that heartbeat is lost over a certain (configurable) period of time, it shuts down the VM and restarts it on another host.

When it comes down to it, I think it depends most on what applications you are trying to protect. There likely won’t be a “one size fits all” type solution so you should consider all options. In some cases Microsoft clusters may give you what you’re after. For others it might be worth exploring a third party tool like DoubleTake or NeverFail.

Each application/VM will have its own SLA so you will likely have different levels of protection. Don’t be afraid of having a blended approach if it meets your needs.