I think it's a good idea to do both. It can take a few months to see results from an SEO campaign, so in the meantime, I'll do Adwords to optimize my landing pages and figure out which keywords convert the best.
Have to agree on that good Seo is the key. I set up a while a website for my mum allowing her to offer some online service and there is a tremendous demand. I just wish the service was as automatizeable as yours. Good luck with that, its a great idea!
