Well I have to toss in my bit for directadmin. It honestly is not limited on what it can do, but it doesn't have a button for doing everything. Updating software in directadmin is a very easy process. I.E. PHP:
That's all there is to it. I'd like to hear what CPanel can do that directadmin *can't* From my experience the majority of it is just that CPanel has built its features into many checkboxes, buttons, and lists within the control panel.
My advice is to get over to the forums at Direct Admin and take some time to research your objectives there. It's a great forum with many good people who spend a lot of time helping other DA users for free. That's one of the reasons I moved FROM cPanel to DA and won't be going back in a hurry!