Well, he is under the wrong impression. Magnolia is using its own CMS for its homepage, and has been doing so ever since before we released the first version (November 15th 2003), exactly since July 16th 2003.
We have built some pretty amazing things with Magnolia, including magnoliaQT (edit videos in your browser, anyone?), Magnolia for Business Processes (draw and document business processes directly in your browser), and Magnolia for Documents.
Magnolia 3.0 will see its beta in the next week, including workflow and versioning, JSR-168 support, JAAS/LDAP, meta-templates including RSS feed generation (and consumtion) and podcast-generation, asset-management, scheduling and an even better new GUI.
As far as kick-ass sites go, thats a very personal perception, - here is one I like, using a quote from Brandon Root (Portent Interactive, who built the site):
"Thanks, you guys made my day Magnolia! We just finished up the Amgen Tour of California, www.amgentourofcalifornia.com, and everyone loved it!
We were very impressed with how Magnolia handled under the load, even before I got caching working. We averaged about 580 hits a second, although that was an overall average and we probably had about 4 times that during lunchtime. This was all running on a single server per magnolia instance, an intel xeon 3.0 ghz processor with 2 Gb of ram."
I think that kicks ass pretty badly, handling up to 8 million hits per hour. Maybe it needs two minutes for installation instead of one, but boy, that one minute sure buys you a lot ;-)