NOTE: Still makes me laugh to see Microsoft announcing amazing new features that VMware had in v2.5!
From the (Very Microsoft Biased) Hypervoria.com site
Managing how you share CPU, memory and storage resources is the key to avoiding performance problems in any virtual environment. Hyper-V environments are no different. This paper will cover some lessons learned in years of experience managing capacity resources in a VMware environment and how those same techniques can be applied to a Hyper-V environment.
Since many of you are already familiar with VMware, we will be comparing Hyper-V to VMware. We will cover how to manage resources (CPU, memory storage and disk I/O) to obtain the maximum safe VM density, how to avoid performance bottlenecks, and how to compute how much capacity there is to add virtual machines for each host and cluster.
The VS Blog 