If your page rank first page on google for keyword xyx, but not #1 spot, will you still buy adwords traffic for xyz ? Let's hear some whys and why nots
This question should have technically being in SEO section.... However, I would still buy the Adwords for the keyword, if the listing was not visible in first scroll....
I would probably use PPC unless the searcher was clearly looking for me (by name) and there weren't any other websites pretending to be me.