Opinions about eZ Publish please

Among other things I run a nonprofit www.InventorEd.org which publishes
educational material and news for the independent inventor community.  I am
looking for recommendations of how to implement a method where people
without html experience can update web pages.  This cannot take the form of
a weblog, in that they need to be able to create content or to edit content.
Think of it more as a virtual book which is continually updated by
nonprogrammers.

I would also like to have access control based on user name + password where
each subscriber to the site has different levels of access.

I would like a method of collecting monthly or annual fees which would in
part determine the users level of accessibility.  Those contributing time to
the site would have access without paying fees and some content such as the
children's section would have free access.

At this time the web site has in excess of 500 web pages and management of
the site needs to be spread among more then one person.  Traffic runs
between 50,000 and 100,000 page views a month.

=== Contest & Judging ===

We will be launching a contest tied to a TV show where people can submit
their inventions for consideration.

There will be a submission fee for the contest.

Submissions will be via web form.  The form needs to be validated.

First review will be by a clerical person screening for certain criteria.
The entry will be tagged for rejection or acceptance in one of several
categories.

Judging will be via reviewing the submission on the web and scoring via web
forms.  There will be between 5 & 10 categories which all have to be
completed.  Judges will all work separately via the web.

All this must be secure.

Suggestions please.  Is eZ Publish suitable for this?  If not why?  What
would be better?

Ronald J. Riley
www.InventorEd.org