IT departments know there is more to selecting software than just the cost. You need to consider the features a business needs and be confident in a products support system. Setting out to compare vSphere vs. Hyper-V without considering the price would seem like total madness to the financial arm of a business but, with so many different factors that can affect the total cost of ownership, it's important to know the functional areas where the two products differ.
There are a number of reasons to leave out the cost when comparing the two products. Both vendors say their product has a lower total cost of ownership and a higher return on investment, but the reality is that there are multiple factors that affect what a business will pay. Some businesses may find Hyper-V gives them the features they need and saves them money, while others may find the exact opposite. In many cases, licensing agreements are subject to negotiation and businesses don't necessarily pay the sticker price. Finally, both vendors offer versions of their product that range from completely free to extremely costly. With multiple editions, fair comparisons are nearly impossible.
Compare feature with more than a checkbox
Some virtualization experts and Microsoft have argued that "the hypervisors are equal and now irrelevant" and that you should now just focus on higher-level management software. Certainly that higher-level management software is becoming more advanced and more important, but I'm not buying that argument. Are all hamburgers from all restaurants equal? No, they vary widely in taste, quality and presentation, even when the cost is the same. The hypervisor is still important and not all hypervisors are equal.
The features should be a part of your vSphere vs. Hyper-V comparison. When you compare the features, it can't be a simple checkbox comparison. In other words, you can't just say "vSphere offers high availability (HA) and so does Microsoft." While both vendors may offer HA, keep in mind that features and functionality can differ greatly. One vendor's approach to HA may be easier to implement than the other, and one may be more efficient. If you do a simple checkbox comparison, you'll also miss important factors like ease of use.
There is no doubt that vSphere is taking the lead on advanced features such as storage distributed resource scheduler (SDRS), distributed switch and private cloud, but I encourage you to take some time comparing more general virtualization features like vMotion vs. Live Migration, where you'll still find differences between the two vendors. Even Microsoft's dynamic memory is very different from VMware's memory overcommit techniques. The real question you need to ask -- which I can't answer for you -- is whether the subtle differences between these similar features will affect your business.
Consider the ecosystem
I don't think I ever realized the value of a product ecosystem before going to VMworld and seeing the massive number of vendors, bloggers, authors and evangelists who all rally around VMware's products. Other than the vendors, most of the people that make up that ecosystem aren't there because they are getting paid. They do it because they feel passionate about the technology. The result of a technology ecosystem like that is a massive amount of blog posts, books, videos, consultants and tools that result in making the product easier to learn, use and troubleshoot. Companies learn to use the product more efficiently and more effectively -- which results in the product being more successful.
You want to use a product with a strong ecosystem. You can measure that ecosystem by going to user conferences, searching the Web for websites talking about that technology, or even glancing at the shelves at a large bookstore to see how many books cover the product.
While VMware has had the edge for many years, Microsoft has a growing ecosystem around Hyper-V.
The all-important trust factor
For me, it all depends on who you trust. That trust is built on things like past history, recommendations and personal experience.
If you have been a Microsoft user for 10 years, love the technology and haven't yet implemented virtualization, Hyper-V may be your natural fit. On the other hand, if you came from a large financial institution that used VMware for years with high uptime, there is no way you would consider any other virtualization solution, no matter the advertised cost savings. Recommendations from friends can also greatly influence our decision in which technology to trust.
Of course, if you can get some positive hands-on experience with any technology, your trust in that product increases. But this idea can work both ways: Let's say that you tried to load ESXi on an old server and it wouldn't work, or you encountered a blue screen while running a VM in Hyper-V. Both scenarios would severely damage your trust in the product.
Finally, your attitude toward one particular company plays into your trust of their technology. For example, if the word "Microsoft" conjures images of unreliable FoxPro databases or viruses, then you're likely to harbor a negative attitude toward Hyper-V. Just like your faith in a particular stock, the government or a religion, your trust will influence which product you choose.
In fact, when you leave the finances out of it, technology decisions come down to features, ecosystem and trust. With the features of the hypervisors becoming more and more similar and the Microsoft ecosystem building, it's harder to provide an objective comparison, which means that many hypervisor decisions will be based on trust.