Some questions about pre-compile options when publishing MVC project

Hi,

there are several option to choose from when you publish a project:

Exclude file from App_Data folder - does this affect MVC projects?

Then if you goto Configure and then Advanced Precompiler settings

Allow precomiled site to be updateable - this puts placeholders where the cshtml files go and compiles the views.

Question is, is this faster only the first time a visitor goes to a site or is it faster every time. If its faster every time shouldnt this be unchecked.

Thanks.