As organizations find their server infrastructures become mostly virtualized and start virtualizing their desktops, they come to realize that vSphere alone is not enough to manage and troubleshoot this environment.  That's why you see so many ISVs offering solutions in this space, and why VMware has finally jumped into the fray with vCenter Operations.  I've been a big fan of vCOps ever since its release earlier this year.  It does a great job of boiling down all the available data points into an easy to understand format, while still providing the ability to quickly drill down during a performance problem.

Xangati is another vendor in this space that I find really impressive.  They are taking a different approach.  Their approach is to not necessarily boil everything down to über-simplicity, but to give you a more holistic vision of the entire environment, along with all the relevant data points.  They're doing this because of the inherent complexity of a virtualized infrastructure.  There are many moving parts that are all interrelated and constantly changing, and a hiccup in one subsystem can have major ramifications in another system.  They call this the "Performance Ripple Effect" (a term I found very interesting).

With their new release this week, they also now can look inside of the Windows guests using WMI and the PCoIP communications within VMware View thanks to their new partnership with Teradici.

If you have a medium or larger VMware environment, I'd highly recommend taking a look at both products.  Both offer free trial periods and can be really useful if you already have a performance problem you'd like to dig into.