I think it is. You can check out mine at http://skilledgraphicshosting.com . Seamless integration. There is also a great whmcs integration component - http://gohigheris.com/. When i purchased the component they took care of all of the installation, great support.
Joomla is free, but the WHMCS integration component is not. The cost for the WHMCS Integration system I am using is $7 a month. You could always hire a designer to do the integration for you, but it would be somewhat expensive
Joomla is open source and is free. Some people develop modules that they charge for but most of the Joomla modules are free. Depending on what your website is for and how technical you are it might be worth looking at WordPress as a good alternative. You can also get web hosting for Joomla & Wordpress with easy 1 click installs as well from 99p a month you search Google
wel website belongs to web hosting for 6 or 7 pages like Homepage,Oder page,customer page , support page and contact us page that integrate with WHM
joomla is the best thing that happened to me . Since i started using joomla i have never stoped loving joomla . It is an incredible CMS