My company is running both. I’m not going to try to persuade you to one or the other.
It’s basically going to come down to what fits your environment best and what you’re comfortable with.
Not all your applications/servers will run well virtualized and until you know the volume of servers and VM density your planning on deploying it’s going to be difficult to weight the gains you’ll get from thin-provisioning & memory over-allocations gains with VMware.
VMware has been around longer and has proven it’s technology with #1 marketshare. Hyper-V has done very well with a much shorter learning curve.
If you’re a heavy linux shop or really cost conscious look into KVM or Zen. It’s not going to have nearly the feature-set but you’ll save a ton of $$ to startup and get your virtualizated feet wet.