I am currently building a site for my hosting company, I am using HTML pages and I link them with WHMCS for orders & support.
Do you advice to use a CMS instead?
I was little worried from using a CMS, from getting an exploit through the CMS and I felt HTML is more safe and since my site isn't dynamic and WHMCS provide me with what I may need more no need for a CMS.
What's your advice?
Is there any popular hosting providers like, hostnine.com or wiredtree.com that use a good CMS I may not know about?
Our site is like yours in the sense we don't use a CMS, We used to run WordPress but there wasn't a need for it so we reverted back to HTML, and it hasn't caused any issues. The only down side is you have to spend a little longer if you want to change a price of a package.
My best advice would be to determine your long-term ideas and compare with your abilities, time and willingness to learn.
When it comes to programming and coding I'm pretty much lost, its just not my thing. This is why I found CMS's to be great - low learning curve, lots of materials, great flexibility and functionality. Not only that but some CMS's like WordPress and Drupal have great SEO options and plugins and you can better market your website.
But, as DH-TimD stated, your project might be quite small and you may not need such scripts and just stick to HTML. At the end of the day, as you want to establish yourself in the hosting industry you might already know that its a constantly changing business and its better you keep up with it