I'm same boat as you mmidgett.
Was using debian 6 + ISPConfig for almost two years, then at July/2013, I did a distro-upgrade and then my nightmare begins...
Lot of errors and slow performance.
Now, in december I have plans to format all and start from scratch, this time I will try the BSD world, I got amazing reviews and benchmarks on DragonFly for webserver and database server.
I did an look on zPannelCP
also, but, seems this CP doesnt support multiple servers like I do on my setup:
1 Primary DNS Server
1 Secondary DNS Server
1 Database Server
1 Cache Server (Varnish)
1 WebServer Apache
1 Mail Server (Dovecot)
1 Subversion Server (Git)
(As firewall I use pfSense)
Without ISPConfig support i will try mix this tutorial: