Quick answer: BOTH
If you are offered to take either 2 lotto tickets or just 1, which option would you take?
When Google Search results are concerned its always better to have two listings on the first page than just a single one. Some customers will click on your Ad while others click on your organic listing. Bottom line: your chances of capturing a visitor are doubled. Getting as many visitors through to your site is why you are pursuing SEO/PPC in the first place!
Best strategy is to run your PPC (Google AdWords) campaign while your SEO campaign is building up. It will take a while to start seeing results from SEO, whereas AdWords will start showing your site on Google straight away.
Once your SEO has kicked in and you are visible in organic search, there really is no reason to stop AdWords, unless you simply can’t afford it.
First 4 listings on search are reserved for Ads. The closest you can get to the top of Google organically (Free) is position 5.
But why would I want to pay when someone clicks as opposed to just getting a free click? Because there is no guarantee a searcher will click on Your organic listing – and so you might miss out on that customer altogether. Having an AdWords ad show up in the results will double Your chances of getting that user to visit your site.
One area where you would not need to run AdWord if you already rank organically is for your brand name searches. You are likely to show up on top of results for your brand name organically and its less likely that competitors will be bidding on your brand. There isn’t as much benefit to having both your listings right after each other. With that said, brand name searches usually carry very low cost per click so even if someone clicks on your ad, it won’t use up too much of your budget.
SEO might or might not get you to the first page of Google Search. There are no guarantees. AdWords on the other hand (if executed correctly) almost guarantees you a place in Google. Cover both angles and double your chances of a win.