At the data-center I've got 6 ESX hosts running around 40ish total vm's locally not on a SAN box. Recently I paid our normal maintenance license fee's and thought about the wonders that be out there that are open-source.

I was just wondering if anyone has migrated away from ESX, and how it went converting the images over. I had done a bit of homework on a couple options and of course my vendor is really pushing
hyper-v (they're a gold partner) but I wanted to know how others experiences went.

Personally I'd love to check out Ubuntu's offerings but not sure how that would go with the owner.

Also if this was posted somewhere, I apologize. I did do a search and found a few things but nothing too generalized and some was out-dated.