3.5 years ago we chose our currect virtualization stack. One important issue was replication to another site which was already using equipment from a certain vendor, the other one was it had to be VMware -based. Send in the pre-sales consultants and after a few meetings we saw where this thing was going to. We ended up with a configuration that kind of suited our needs. We were very pleased with our Dell server hardware (PowerEdge R710). But on the storage side, we missed the "flash revolution" and you can read other storage related rants on my blog.
Over the years, we did tweak the system a lot in-house, ditched NetApp backup tools and brought Veeam into the game. As a result we now backup to cheap Dell boxes, and the process has never been easier. Dedupe is not handled well in Windows Storage server 2012R2, but if necessary we'll add a cabinet with cheap SATA disks or attach a tape library. We also were considering PernixData to spice things up.
We wanted to use this configuration for the full 5 year term but then new opportunities rose. We immediately noticed our current solution didn't scale that well. We're also hitting some of the limitations of the Essentials bundles. We are better informed now but this by no means makes the job of selecting the right infrastructure easier.
Hyper-v and KVM became a lot more mature and then came exciting new "hyper-converged" technologies like virtual SAN, SimpliVity and Nutanix.
One option we are considering is to combine VMware and the Acropolis hypervisor in one Nutanix cluster, but we're also looking into Flexpod and more traditional setups from Dell and HP. It has to scale a lot as we expect some serious changes.
So, interesting times ahead...