Hello Rowan,
I think the usage of this features depends on your clients environment/client driver capabilities. It would be usefull, if Extreme releases some informations of know working devices including driver release. The informations included in software release notes say nothing about the tested and support feature matrix, but the GTAC knowlegde base have serveral entries with recommendation mostly related to disabling this features because of client related bugs. Would be really great to know whats tested as really working.
Regards
Hartmut