SEO factor is a big Con.
The trend for parallax scrolling websites is as strong as ever in 2014 and those who said it would just be a short term design fad destined to go the way of flash websites are not looking too smart at the moment. There are still plenty who prefer to keep their distance from this style whilst they are many converts will extoll their virtues at the drop of a hat and see them as their go to web design style to impress and wow clients. The reason why there is such a divide in opinion is normally down to different people having different priorities for a website. In the main the pros and cons can be summarized as following: