Properly structured landing page is big part of the Search Engine Optimization. Shell is a hassle-free WordPress CMS Theme. All of the content on this landing page is fully manageable directly from Theme Options, including call-to-action button and its destination.
Testimonials are a powerful selling tool. Many great selling ads are made up of 1/3 testimonials of the company's products or services. This is only a suggestion, since this area is widgetized you can use it any way you please to satisfy your needs.
Headline, Subheadline, brief info above the call-to-action button and including the button, together with its destination link can be changed via Theme Options. Logo is uploadable as well. Three columns you see here are widgets.