I recently configured a new server that came with Cpanel/WHM installed, and I have to say that despite my initial exitement over the it, I've come to blows about whether I'll ever recommend or choose it, or possibly any other "panel" again.
I don't have tremendous experience with Cpanel, I've had it as a client, and figured the 'broke' stuff was due to the administrators, and I've configured it from a fresh install, and alot of the stuff is the same.
I RTFM so I've not had any problems configuring it nor using it for the most part, in fact, cleaning up alot of the 'clutter' and better organizing, labeling, categorizing, and documenting portions of the interface would probably add 100% value to the package.
Including every single option / package / script on the planet by default is just bloatware. I'm going to spend more time removing, double checking, and undoing 'features' and changes that Cpanel /WHM performed than I would have just configuring the server through the command line.
For instance, the default WHM configuration options available to set up BIND allowed a less than desireable configuration, with no visible method to change that. After manually configuring it, I can't really depend on using WHM to create new zones and edit *.conf because it causes syntax errors by just appending to the *.conf file. Now I have some damn popup everytime I log in because Cpanel cant find an A record for the hostname, but it's there, and everything works fine as long as I don't use WHM-lol.
There are plenty of other stories like that one for apache, exim, and the ftp server. Maybe it's because of my inexperience, I dunno, probably.
I'm of the opinion right now that if you're going to create a wrapper around any service, not to mention multiple critical services, that you should spend some time to make the backend more transparent, for each and every service. I'd be happy with less features that were better implemented control solutions for a particular service, than a multitude of partially implemented problems waiting to happen.
I hate to be a downer, well, not really, but so far I'm not very impressed, wouldnt buy it personally, and would rather use the command line and build or learn to build my own features.
Hey if it was free, maybe I'd have nothing to say, but I've always been of the mindset that if I was providing something to people for money, that they could quite possibly depend on for their success, that I would do everything in my power to make it the best possible, and so far I don't feel that you've done that. Take it for what you will, vio con dios or something.