It totally depends on the needs of client, the max amount of resources needed to run the project or website,and actual goals and also the predicted growth and resource usage in the near and far future. For example, if you think your website will not get more than 1000 visits per day for more than 1 year, its better to go with a VPS so you can save a lot and will not pay for lots of unused resources. But if you are concerning to run a website that is supposed to get more than 100,000 visits per day just in a few months, you may not go with VPS as you know you will need to move your site soon and your site may go down for some hours. So in this case you certainly prefer to start your website on a dedicated server that will meet your need for a long while.