Anyone Have Experience with Nessus?

Hello,

I was on the sectools.org top network security tools list and I saw a tool called Nessus at #3 on the list. I have heard and seen most of the other tools on this list on Null Byte and other sites as well but this was the first time I have heard about Nessus. Does anyone have any experience with this tool, and if so how well does it perform compared to other free software considering its price tag for outside personal LAN use ($2000)?

Thanks!

Plague_