Another community difference: How the communities get together. "Drupal has two big conferences each year -- one in the United States, one in Europe -- each pulling in a few thousand people," says DeMet. "Joomla tends to have smaller, more regional events -- which Drupal also does. Having these big conferences lets Drupal developers get together and collaborate."
The entrance of Acquia onto the scene has solidified Drupal's place in the enterprise market, says Christopher Wells, a Member/Developer at Redfin Solutions, LLC. "This means that the 'big guys' have nothing to fear about implementing an open source project -- they can always get support for their Drupal installation, even if everyone in their organization who knew anything about the Drupal site left tomorrow. I believe this is what has helped pull in major sites like whitehouse.gov for Drupal."
Technology aspects may drive your choice, notes Mitch Pirtle. "The hosting company may not support PHP 5, which means you have to stick with Joomla 1.5, which is going into maintenance, or go with Drupal, which doesn't yet require PHP 5. If you're using younger PHP programmers, they'll probably get up and running faster in Drupal -- I think there's a steeper learning curve in Joomla."
Pirtle adds that "if you don't understand basic object oriented techniques like object inheritance, you'll have more trouble with Joomla. With Drupal, you can typically find the piece of functionality you want to change in one spot, and make your changes, where Joomla is more sophisticated in its architecture, and you have to work in multiple locations to fix something like a particular theme."
Palantir's DeMet prefers Drupal, for scaling and flexibility. "From a technical perspective, I work with Drupal because of the kind of sites we build. There's a type of site that Joomla is good for, but if you try to scale it up too much you can hit a ceiling in terms of capabilities." Also, says DeMet, "Drupal is more like a framework to me. It's in the middle between a CMS and a framework, with the flexibility of a CMS and the functionality of a framework. We can do tight third-party system integration with Drupal that wouldn't be possible with another system."
David Lohmeyer, Web Coordinator at non-profit Acton Institute, says, "With Drupal, it is easy to move a site and set up new sites quickly. It's even easier in Drupal 7 with the new sites.php configuration for staging/dev sites. It's great for multi-site setups by using pluggable folders under the "sites" folder so you don't have to maintain multiple installations of Drupal.
Lohmeyer does ding Drupal with a few dislikes: "The 1 time out of 10 there isn't a Drupal module it's sort of a pain. It's easy to integrate your own script though and use Drupal as the "shell" for access control and other site features. Unless you have a preconfigured installation you use for sites, configuring a new site takes a decent amount of time. And the learning curve is high."
On the other hand, Lohmeyer chose Drupal for one site with over 3,300 content pages (migrating from a proprietary CMS), "because of the ability to provide all of the complex features like dynamic layouts, lots of menus, great SEO, and more," and for another site, "because of the Webform module. With some custom jQuery, Webform is able to handle very complex class registrations and prerequisites for a specific form."
Documentation, ease of use, orientation
Chuck Hriczko, an application developer at Accella, Inc., who worked on both Joomla sites and Drupal sites, says: "Generally, if I'm going to use one of these CMSs, I'll use Drupal. What I like about it, there's generally better and more documentation, and where the documentation is inadequate, the support community can provide the information -- generally, the documentation you'd need would be developer-specific (e.g. if you need to add a new module, Drupal has more info.).
"Joomla is geared more for designers, making it easier to do some things," says Hriczko, "while Drupal is more for developers, it has more extensibility, you have more power to create better modules. You have to figure out what your needs are. If you want the power to change it however you want: Drupal. But that requires being more of a developer. Joomla would be better if you want something that's easier."