Is there any real benefit to using ASP.Net Authentication with ASP.Net MVC?

Programmer Question

I've been researching this intensely for the past few days.

We're developing an ASP.Net MVC site that needs to support 100,000+ users. We'd like to keep it fast, scalable, and simple. We have our own SQL database tables for user and user_role, etc. We are not using server controls.

Given that there are no server controls, and a custom membershipProvider would need to be created, where is there any benefit left to use ASP.Net Auth/Membership?

The other alternative would seem to be to create custom code to drop a UniqueID CustomerID in a cookie and authenticate with that. Or, if we're paranoid about sniffers, we could encrypt the cookie as well.

Is there any real benefit in this scenario (MVC and customer data is in our own tables) to using the ASP.Net auth/membership framework, or is the fully custom solution a viable route?

Update: I found one person who seems to have come to some of the same conclusions I have:

ASP.net membership is a poorly
engineered API that is insecure out of
the box, is not well maintained, and
gives developers a false sense of
security. Authentication is a weekend
project if you aren't building a
framework, but still, most .net
developers blindly follow the official
APIs, assuming that a major
corporation like MS can put out
something decent.

Find the answer here