There can be many factors while considering any of the platform for one’s businesses, one of the major factor is security which is more redundant in dedicated server as one has everything centered around one user, one owns the server it means he is the boss,no more limitation in bandwidth usage,Better Performance. They do not have to share space, bandwidth or any other feature with any other website. It is most suitable for websites that expect a heavy amount of traffic. Whereas, in shared server one shares the IP with other users,Slow Server Response Time, generally Server Crashes Regularly. Shared means multiple websites hosted in the same location. So, in a server, there are multiple websites sharing the space, bandwidth and so on. This type of hosting is ideal for small business as well as new webmasters who are trying out for the first time. It has some limitations in its resources.
To sum it all one can say that both the web servers has its advantages and disadvantages. It all depends upon the user’s requirements. But in a way a dedicated server hosting is always a better choice then a shared server.