Whats the problem with cPanel?
I'll give you a long answer of what I did and why...
It doesn't scale and it more often than not will prevent you from customizing your server outside of the panel. Scaling is the main problem. I just started using Interworx so what I've done is setup 2 nameservers (Each on a $3 VPS) and then installed Interworx on a very powerful dedicated server. I'm using that as my cluster manager. For now it hosts all of my sites on its own but if server load winds up becoming too much for this dedi, I can deploy another Interworx server as a member of my Interworx cluster to take some load off of the main server. My cluster nodes are probably going to be VPSs (Cheaper than my dedi/main server).
What you sort of wind up with is your own hosting cloud. I've gone through all the options and I haven't come across anything I need to do that I can't. Many people (Including myself) have been asking CPanel to implement scaling solutions for many years but they never make any plans to do it, feature requests that fall on deaf ears.
It depends on your needs. If you don't need to handle that much traffic, mysql queries, disk usage, etc. or don't want to have more underlying control over your system then there's nothing wrong with CPanel. On the other hand, why not be prepared just in case you wind up needing it? Otherwise, you'll wind up having to migrate anyway which is annoying. Luckily, Interworx can mass import all your accounts from your CPanel server so it wasn't too bad but of course you'll spend some hours changing settings and whatnot.
I have some high traffic sites and I really needed to upgrade from the VPS I was using (It was getting bogged down and you can't just add a second CPanel server to help you) so when I went shopping for a dedi and then learned of interworx it was a no-brainer. The only thing I miss is the nginx caching I had installed on WHM but I'm about to replace Apache with Litespeed anyway so I won't need it. Litespeed is a great drop-in replacement for Apache as it greatly outperforms it. Nginx outperforms it as well but then you can't use Apache directives and .htaccess files.
So right now my hosting sauce is: Dedi + CloudLinux + interworx + Litespeed + Cheap DNS servers and future iworx VPS servers as load invariably increases. The central server doesn't have to be a dedi. I just wanted assured performance on the main server because I have a lot of traffic and mysql requests running on it at the moment.
Not to geek out over it but I'm very excited and happy with my new setup. I was afraid I wasn't going to be but I am.