Having your own guaranteed CPU and RAM gives you a great deal of autonomy. You don’t have to share them with any other accounts, so no matter what anyone else does they will never slow you down. Regular shared hosting is okay if your website traffic doesn’t change much, but if there’s a chance it might need more horsepower then VPS is far more flexible. And from a security point of view, the fact that VPS hosting accounts are cleverly separated on the same server makes them much more robust than a shared hosting solution.
The answer to this question is a definitive “maybe.” Since you’re looking at this site, you might be a Web designer who has a few sites, an online portfolio, and a couple of long-standing clients whose sites you manage. Is a VPS for you? Well, you’ve most likely outgrown a shared platform, and as a professional, it won’t do to have your site run poorly because another site that you share a server with is using more than its fair share of resources. A dedicated server could be overkill – if you don’t need all the resources on a consistent basis, you may not be able to justify the expense.