WCF/WF - Difference in Hosting a wcf service as a windows service in server and in IIS?

what points are to be considered while hosting a wcf service  as a windows service or in  IIS? what difference does it make if the wcf service is hosted as windows service or in IIS as both would be running in the same server?

Client access and firewall restrictions. HTTP (IIS) is a protocol that many client applications types can easily interact with and port 80 is rarely blocked.  Depending on you configure your windows service, you may create issues for yourself.