[TYPO3] Is Typo3 the choice for me?

[ammad jami]

Hello

I am in process of selecting a CMS. I actually have to develop a big portal
for a certain industry. This portal will have 100+ sub portals. Each
subportal will have registered users and each user will have a site of his
own for maintaining his personal content on his personal site. There will be
around 1000+ users per subportal. Moreover, each subportal will have blogs,
communities, groups etc. as well as some shared content sites. Each user
having an indpendent site on a subportal, may also need to connect to an
email server where an email account rests for him.
So the question is, Is Typo3 a good choice to fit these needs?
If it is, then what problematic areas will I deal with? Any specific
considerations?suggestions?

By the way, till now the race has narrowed down between Typo3,Plone and
Drupal.

Thanks

candidcarper