One of the often overlooked features of XenApp is truly understanding the load evaluators. As a consultant, I commonly see environments using only the Default Load Evaluator. If I am lucky, they might be using the Advanced Load Evaluator. Rarely do I find organizations actively monitoring or customizing their load evaluators.
Load Evaluators have not changed much since Presentation Server days, but amazingly they are not commonly optimized. Every environment and every workload is different, so whichever load evaluator is implemented may vary, but they should be customized and monitored.
Read more on my full article over at TheGenerationV: http://www.thegenerationv.com/2011/06/technical-deep-dive-xenapp-load.html
Also, be on the look out for my new programming endeavor.. the XenApp Audit Tool. I have incorporated the QueryDS analysis into my application. Coming soon!