Hi!
So I just took a look, and I asked a few of my colleagues to check as well, and we all found the site slow to load (several seconds) I'm not entirely sure it's because of WP Super Cache, though. A few questions:
1) Have you tried "Use mod_rewrite to serve cache files" instead of Use PHP ?
2) If you've already pre-loaded the pages, I'm not sure why you're doing it again every 100 minutes? Does the content change that often?
3) Is this site on a shared host, or a VPS, or something else?
