Buy business web template with total customization option. You may get layouts in the market designed superbly but with little scope of customization. On the other hand if you go for open source developments like the Drupal, Joomla or others then you should buy layouts designed for particular themes. Otherwise your developers or the designers will face problem to make layouts completely fit for your business. Even in SEO related changes there will be problem.
The first time you make a WordPress site it may be a bit tricky for you. If you are not very well versed in PHP and MySQL this site can be all but downright confusing to you. Taking it slow and learning to tap into the functionality of WordPress is ideal however and will immensely benefit you in future sites, therefore you should really consider tapping into it for one site at least to see how it benefits you.