No sample resumes are accessible. A competent resume writing service will provide a number of samples for review. You can assess the quality of their work only if have these samples. If there are no samples available on their website ask them for the specimens of their work. If they are unable to provide satisfactory examples of their work you had better opt for another service.
The template of the resume which is actually the outline or the structure of the resume decides the positioning of every element of the resume. If this positioning is clear and clean with an equal weightage given to every element it appears that there is a flow in the format and so the resume appears attractive. Such a resume neither looks like a piece of art which shows that you were keen about the outline of the resume rather than the content nor does it appear as an essay.
Functional format is best for those who are switching their career or have large employment gaps on their resume. In this format, you dont have to list the joining or resigning dates of the previous employments. Functional format will hide your employment gaps or your job switching.