I, too, have issues with vendors and our own product company blame VMware or virtualization in general for their own poor performing application.
In most cases, I avoid telling anyone that their application or server is virtualized in any way. I purposely do not tell them, or they will simply jump to the conclusion that its VMware.
Most recently, one of our sister offices was running ESX 2 and a third party application kept returning memory errors after a coupel hours of operation, basically depending on how many transit items the application processed. To me it seems like a memory leak, since most of the code was C++ and not managed code. The third party company sent down one of their developers and as soon as he herad it was running under VMware said that he wouldn't recommend it. Even though was running in other locations fine with less volum; including ours.
The problem was later blamed not having the latest Microsoft patches and service packs applied to the O/S. Which doesn't make sense either. The strange this is, they rebuilt the server and the problem went away.
I suspect it was the constant updating to this application of the course of 12 months. There were a tone of .DLL files and third party components... many of which needed to be copied and registereed manually.
Anyway, I really hate it when folks blame VMware on their application issues.
Sorry for my rant.
