ALL YOUR VMs ARE OURS
I believe this is based on Marc Farley's Project Hoover patent.
Microsoft has fired another shot in its campaign to win over VMware users, in the form of an updated Virtual Machine Converter that can move virtual machines from ESXi to Hyper-V. It's no secret Microsoft covets VMware users: in recent times it has created a certification helping VMware users to grok Hyper-V. Redmond also uses …
Even though knowledgeable and astute technologists 'know' that VMWare ESXI running on Enterprise Linux in a Linux based Cloud - like OpenStack, is significantly more reliable, scalable, powerful and especially secure than the these solutions running in Microsoft Azure and Hyper-V Cloud, there are many naive and simple minded Microsoft clients who will always fall for the "easy migration", (supposedly) lower costs pitch from Redmond.
Fortunately for Microsoft there are still doofus VMWare customers who still worship and admire Microsoft enough to make the company's bait and switch crap a success. Just look at the quantity of Azure crashes and security vulnerabilities suffered in the past year compared to competitors who are infinitely larger in scale, to prove that such a move is ridiculous.
Simple - Use it it cautiously, demand the best, plan for the worst. If historically they have not delivered above and beyond the SLA you need, then find another solution for your critical systems.
We've recently been investigating using Cloud services such as Glacier for offsite storage, but I would never in a million years put business critical applications or systems on a 3rd party platform that a) don't offer a point of contact through to the engineer(s) running the system as standard (Why pay extra, just to get answers to the platform providers screw-up) and b) I have absolutely no control over.
Why? At the end of the day Uptime and Risk Management are part and parcel of working in IT. Don't put yourself in a position that you cannot manage or poses a risk to the company. That is not to say you should not take difficult decisions, but ensures they are measured an appropriate.