I don't have a lot to add here. I've been experimenting with uWSGI in place of PFM in my server stack and XenForo is the main web app on two of my sites. uWSGI at its heart is for Python but it also has a fully functional PHP plugin. I've been toying with Nginx+uWSGI for PHP w/ ACP on my personal server for a few days and I haven't run into any issues. Any XenForo uWSGI-specific stories to share?