1. This is the framework for building HTTP services with easy and simple way.2. Web API is open source an ideal platform for building REST-ful services over the .NET Framework.3. Unlike WCF Rest service, it use the full featues of HTTP (like URIs, request/response headers, caching, versioning, various content formats)4. It also supports the MVC features such as routing, controllers, action results, filter, model binders, IOC container or dependency injection, unit testing that makes it more simple and robust.5. It can be hosted with in the application or on IIS.6. It is light weight architecture and good for devices which have limited bandwidth like smart phones.7. Responses are formatted by Web API’s MediaTypeFormatter into JSON, XML or whatever format you want to add as a MediaTypeFormatter.

1. This is the framework for building HTTP services with easy and simple way.2. Web API is open source an ideal platform for building REST-ful services over the .NET Framework.3. Unlike WCF Rest service, it use the full featues of HTTP (like URIs, request/response headers, caching, versioning, various content formats)4. It also supports the MVC features such as routing, controllers, action results, filter, model binders, IOC container or dependency injection, unit testing that makes it more simple and robust.5. It can be hosted with in the application or on IIS.6. It is light weight architecture and good for devices which have limited bandwidth like smart phones.7. Responses are formatted by Web API’s MediaTypeFormatter into JSON, XML or whatever format you want to add as a MediaTypeFormatter.

1. Choose WEB API for RESTFul services. WCF also capable of doing RESTFul but not useful to get all features of HTTP. 2. Choose Web API when you want to create a resource-oriented services over HTTP that can use the full features of HTTP (like URIs, request/response headers, caching, versioning, various content formats). 3. Choose Web API when you want to expose your service to a broad range of clients including browsers, mobiles, iphone and tablets.

Please explain what you mean by " REST-style services"

Use ASP.NET Web API to create HTTP-based services that are accessible from a wide variety of clients. Use ASP.NET Web API if you are creating and designing new REST-style services.