These are service managers in redhat based and debian based systems respectively.
I have worked mostly with chkconfig. Interface wise, it is much better than the windows service manager. They work on top of simple abstractions like files and directories, and as such give you immense power to customize the startup of services.
chkconfig allows you to specify run levels at which you should start the service. I have used this to manage the dependencies between the services. I am not sure it gives any other mechanism to specify this.