Developing a website for 3 mln. users: SharePoint OR pure ASP.NET?

Question

We need to develop quite a powerful web application for an investment bank. The bank IT would like us to build it on top of the SharePoint platform

Answer 1

I would build this on SharePoint. It is quite suitable for big sites and many sites have already been built on it: topsharepoint.com

SharePoint (like all complex applications) does require sufficient knowledge that you do not seem to have at the moment which is a big risk in my mind. Don't listen to the nay-sayers though.. lack of knowledge is a common problem for devs dealing with SharePoint but it doesn't mean you can't make it do whatever you want.

Regardless, what other options do you have? I think the days of building completely custom CMS's have passed just as building completely custom Intranets are not cost effective anymore. There are many competitors to what they want to do with SharePoint (Umbraco, Sitecore, Sitefinity, etc) and most of them seem better than 100% custom.

So the answer might be neither ASP.NET or Sharepoint..