When it comes to speed, AdWords is the clear winner. It can take a few months before you start to see your SEO working, and it will take even longer to get your website to the top of the organic results. On the other hand, AdWords can get your paid ad on the first page of the search results instantly.
As previously mentioned, AdWords runs on a pay per click scheme. You are able to choose your daily budget which will dictate how often your ads appear.
If you are looking for instant gratification, then look no further than AdWords. AdWords will deliver you instant results. However, as soon as you stop paying for an AdWords campaign, these results will instantly disappear.
It will take longer to see results with SEO. However, when you finally start ranking on page one, you will see a definite increase in traffic to your website, and you will be not charged for the clicks. To sum it up, SEO will not provide instant results, however, it will provide you with more affordable and sustainable results.