Which is perferred – a standalone login page or a javascript popup over a MyAccount page?

I am designing a new website, and am thinking about the UX for accessing a personal account page. Is it "better" to have a standalone login page (and then redirects to My Account details), or a Javascript popup which is on top of the My Account page? In the first situation, the interface will be "cleaner" (less potential clutter appearing to the user), but in the second scenario, it might appear like a faster, more streamlined UX. Are these correct observations? Any other reasons pro/con to consider one over the other?