Everything is pretty easy to use. I'm guessing as you're familiar with cPanel that side of the admin isn't a problem but just in case, this is a very easy to use graphical interface where you can make changes to email, ftp, domains, files etc. etc. etc. If you go to
http://www.cpanel.net/products/cpwhm/cpanel11/demo.htm and then choose domain owner panel you will see how the backend looks.
Regarding the admin side for you, Modernbill allows you to clearly find info, invoices etc. and it's very simple to sort things.
