In Shared Environment, multiple Customers share the resources with all Security and privacy to Data. This is the best Environment for smaller companies with limited Users.
You can choose Dedicated Environment if you are looking for a sub-domain of your choice to run OmniStaffer and use the resources dedicated to you.
VPS Hosting is the perfect choice for those who wish to start small but have the ability to scale up very quickly. VPS provides you with Private Resources, which give you the benefit of dedicated resources, but you pay a far cheaper rate than you would if you were to rent out an actual dedicated server.