There is no doubt that shared server and dedicated server have multiple advantages. However there are certain drawbacks in both these offerings which by large are taken care off in a VPS server. 

Let us throw some light on the key differentiating factors:-

Cost 

A dedicated server is costly. It is advisable for only those businesses that have constant high web traffic. Users not experiencing consistently high traffic on their websites need not avail dedicated connection as they will have to pay the fixed rental cost irrespective of their usage. Only high traffic captivating sites can meet the desired ROI by availing services of a dedicated connection. For others, VPS server is certainly the apt solution. Although shared servers are cheaper in cost they have many other security risks.

Security

In a shared server, neighboring websites can act as a threat to your website giving way to hacking opportunities and other malicious activities occurring on your website. In a VPS server, each website is virtually allocated different IP address, separate network bandwidth, disk space, etc.

Complete Control

You cannot install applications/software as per your business need in a shared environment. In VPS server, this problem is resolved as you get complete control over your resources.

Better Performance

In a VPS server, performance is certainly escalated as compared to a shared environment. Sharing the server can lead to interruptions in service as resources including RAM, CPU utilization, processor speed, disk space, etc. are shared among multiple websites. Hence, there are chances of other websites drawing maximum resources attention leaving extremely little for your website. Service degradation can lead to loss of customers.

Therefore, there are a fleet of benefits one can avail by choosing a VPS connection however you need to be careful while choosing VPS hosting provider. Go for an established and well-known service provider to get efficient and effective service.