It really comes does to how quickly you want to start generating leads through the website. SEO is a process that takes 3-6 months if there is not major competition in your market/business niche. But, if you are planning to make the website a key piece of your marketing strategy for the long haul - then yes you want to invest in SEO and get your website ranking.
For quicker results, paid traffic is the way to go. GSL can setup campaigns that bring traffic to your website and you will pay for each visitor, What the visitor does after that is up to you. GSL can also setup landing pages where the visitor hopefully enters their information or calls you directly - LEAD!