ASP.NET Cache class vs. MemoryCache class

[spymode]

I am creating a website on ASP.NET 4.0. I am unsure whether to use the old ASP.NET Cache class or the MemoryCache class introduced with .NET 4.0.All I can find are reasons to use MemoryCache for non-web applications, but no pros or cons when programming websites (where I obviously can use both classes).