<p>Has anyone had experience with MySource Matrix as a content management system? If so, thoughts/opinions/comments? </p>

<p>Thanks in advance. </p>

Absolutely excellent. It takes little while to get used to how it does things with its asset structure, but it is really flexible and powerful. Simple edit interfaces are great too.
Make sure you give it enough hardware. If you want dynamic content without caching you need heaps of grunt to make it hum.