website project assessement - how hard/easy would this be?

hello,

I have a website project pending and i hesitate between using ruby on rails or a CMS like joomla for it. Therefore, i welcome your insights to assess of how much work would be needed using RoR and if it is a better choice than using the CMS. ...Instead of talking a lot, let me present what the website should exactly do. :wink:

Basically, the website is intended to be a sort of vault for free texts. It should store pdf files representing various kind of texts, from small articles to big ebooks. These are published freely by any user, like videos on youtube, but with an effort to garantee that they are authorized by their true authors. The site should have following features: -a user can add a text -the text is added along with tags -texts can be searched according to a mix of: title / author / date / tags -people can review texts by giving a rating and a comment -people can report texts which are not authorized to be free by its original author -when two different persons reported the same text as unauthorized: the text is automatically removed from search result and the administrator is notified and can confirm/infirm it. (*) -when an account has posted two unauthorized texts, the account is deleted and the IP as well as the mail are black-listed. (*) -a forum associated to each text to ask/answer questions, report errors, give suggestions -authors can update the text, add an errata -donations -two kind of registrations, one free and one paid with different privileges

How hard would this be? ...i'm especially concerned about the starred (*) features. Would you take RoR or a CMS like Joomla?

thanks