I believe one achieves a little better granularity than the other.
The WFW exceptions are basically telling the operating system that if a particular application wants to open up listening ports, LET IT! So if you add your SMTP server application in the WFW exceptions list, it will be allowed to open up any listening ports it wishes as well as establish outbound connections at will.
The Advanced-settings-services you are referring to is allows you to be much more granular in that you can just say "Hey I want port 21 to be in listening mode. I dont care what application is doing the listening, but just know that i dont want the firewall to drop packets destined for 21 because its going to be listening. (Thats if you were hosting an ftp server obviously, but you get the idea) And this tab provides even a further level os granularity since it lets you define which nic you want to apply this particular rule to.