WCF has [ServiceContract] attribute attached with the class.
WS has [WebService] attribute attached with the class.
WCF has [OperationContract] attribute attached with methods.
WS has [WebMethod] attribute attached with methods.
WCF can be hosted on IIS, WAS, of self-hosting.
WS can be hosted on IIS.
WCF uses using System.Runtime.Serialization; namespace for serialization.
WS uses using System.Xml.Serialization; namespace for serialization.
WCF support HTTP, TCP, MSMQ, P2P transport protocols.
WS support Http protocol.
WCF supports XML, MTOM (Messaging Transmission Optimization Mechanism), Binary.
WS supports XML, MTOM, DIME (Direct Internet Message Encapsulation).
WCF provides reliable security for messaging and transactions over net.
WS doesn’t provide method level security & message delivery isn’t assured & can be lost without acknowledgement.