The redirect loop is a problem that exists between IIS and the Url Master module.  To solve it, you need to change the setting for /default.aspx redirects in the 'Friendly Url Settings' page.  This removes the redirect from /default.aspx to the site root. 

If you're afflicted with the /default.aspx redirect loop, I currently don't have a solution because the problem appears to be within IIS.

As for the non www redirection, it's been logged as a bug and will try and fix it.  In the meantime, you can use another setting in your web.config, whereby you remove the 'redirectToSubdomain' attribute, and replace it with 'usePortalAlias="0,www.alias.com"' - where 0 = your portal Id, and 'www.alias.com' = the portal alias you would like that portal to use.

Actually the missing 'redirectToSubdomain' attribute is the reason it isn't working.  You can always add in redirectToSubdomain="" - that will redirect to the domain.com from the www.domain.com value.

You can also use the 'usePortalAlias' value - it specifies which portalAlias should be used for the specified portal id.  This can be the www.domain.com version or the domain.com version - whichever you prefer.