Expression-bodied properties vs. {get; set;}

When I have Visual Studio 2017 generate properties for me, it will always use the new expression-bodied properties, for example:

private static string username;
internal static string Username { get => username; set => username = value; }

Is there any advantage of using this style over the following or is it just a matter of preference and readability?

internal static string Username { get; set; }