It totally depends on your business. If you are conducting a short term project then you can use Google Adwords because its the best source to get some visitors swiftly and make money. If you are having a long term business plan then you need SEO organic rankings. There are numerous advantages in it. I have listed down the advantages as follows
1. Cost Effective or Free
2. More natural
3. It would reduce your bounce rate
4. Customer Retention (more chances of customer retention because they surf and contact you)
5. It would improve your Corporate brand