With any marketing strategy you decide to use, I always say test, test, and test again. The only way you'll know which one is more beneficial for you is to test both strategies. Since using Craigslist is free, it will only cost your time to see if it works for you. I've used Craigslist as a marketing strategy for years now and receive a good amount of business from it. If you are handling your own marketing, take the time to learn how to post to CL not only for people that search CL, but to also get ranked in the search engines.
I cover marketing on classified ad sites such as CL in my book "Can Your Customers Find You Online?" I go over how to optimize your listing for the search engines. www.seoallianceteam.com
Links: www.seoallianceteam.com

Best thing to consider is your content. Make sure the content on your website is relevant to what you are advertising yourself as. Your domain name can help a great deal as well.
Using social networks is a great way to even the playing field to help with SEO because social networks are popular and high traffic sites. Focus on content and keywords and you wont go wrong. Go easy on the keywords though, too many redundant ones pass you off as a higher risk of spam than legit content.