Hi guys.

I am developing a multi-site network of sites that are independently operated (for the most part) and share data like blogs, news, photos, videos, etc.
I just settled on a Joomla, WordPress and VBulletin integration and started searching for developers when I thought I should really make sure Joomla is the correct choice for this type of setup.

I'm not looking to create a pissing contest between the various technologies or which one is "best". We all know all the major players have their benefits and drawbacks and many times it comes down to personal preference. I'm simply looking for the best option for MY situation.

The big 3 I'm considering are Joomla, Drupal and Expression Engine. I'm certainly open to other suggestions but I'd prefer to go with software that has large user bases. I've currently settled on Joomla because of the combination of large user base, flexibility and amount of extensions, modules, etc. From reading the interwebs I got the impression that Drupal was difficult to learn and rigid. Since I'll be hiring developers to do the work I couldn't care less about the learning curve of Drupal as long as the final product is what I need.

As I mentioned before, this will be a network of sites that will share the same framework and share some data. Each site will be operated independently where news, blogs, videos will be added by each site's admin but each site will have areas where info/data/news will appear from other sites in the network. Each site will have the ability to control some advertising space but there will also be Ad spaces in each site that will be controlled by the network. Most importantly is an easy to use back-end for site admins, bloggers, contributors to make updates, change colors, logos, banner ads, etc. Scalability is important because we need to be able to add sites quickly to the greater network as needed. We'll need to ability for site admins to set user permissions as well as the ability for admins of the network to control network-wide issues with power over site admins.

In your opinion, which CMS system gives us the best chance to achieve these goals? Does one excel any more than another at this type of setup?

Thanks for your time and I look forward to your opinions.