Joomla and Mambo CMS have been developed by the same professionals of web design industry. So, they possess a lot of common features. For example similar code, system requirements, etc. At the same time new releases of Joomla will differ from Mambo. Having compared Joomla and Mambo CMS‘s you can notice that Joomla has more options, better security issues, regular updates, additional Built-in-Applications, etc.
I would say the number one benefit to website templates is that they‘re going to save you from having to wait for somebody else to get done with your website. You won‘t control don‘t you? Well website templates allow you to have a personal website set up within a few days after purchasing. All you would need is to select the platform you want and then choose templates that are going to suit it. Now compare this to trying to do everything yourself or hiring a professional web developer. It can take days before the product is even ready to get started.