They have different design goals. Async in F# works better for F# applications. Tomas Petricek wrote a couple good articles [1][2] comparing both approaches to

They have different design goals. Async in F# works better for F# applications. Tomas Petricek wrote a couple good articles [1][2] comparing both approaches to async computations. [1] http://tomasp.net/blog/csharp-fsharp-async-intro.aspx/ http://tomasp.net/blog/csharp-fsharp-async-intro.aspx/ [2] http://tomasp.net/blog/csharp-async-gotchas.aspx/ http://tomasp.net/blog/csharp-async-gotchas.aspx/