You don't specify what kind of a project you're planning to launch using these CMSs.
In terms of management, Joomla is certainly easier. However, if your website would require lots of customisation, it may be better to start with Drupal right away as it is more powerful, but mind that the learning curve is the steepest.
Both of the CMSs do have huge communities, this is easily noticeable
by the number of Drupal modules or Joomla extensions that are
available. Drupal is more open and less centralized. While there is a
central website for Drupal that has a lot of information and
documentation, there are thousands of other sites. So, it is a good
chance that if you do a search for a issue with Drupal, you will be
directed to a third party website. Joomla has a central website that
is wiki-based. It is often updated and has great information. So it is
more of a one-stop shop for issues with Joomla than Drupal.
While the CMSs are open source, only Drupal’s extensions (sometimes
called modules) are 100% GPL. This means all the extensions you can
download and use for free. While Joomla does have free extensions,
there are also numerous commercial ones.
Support of Extensions
Related to the above difference and one downside to the GPL and free
extensions are the support for them may be non-existent or limited.
So, if you have a problem with a module, you will have to find the
Since Joomla does have commercial extensions, you have the support for
these extensions if you ever need it.
this is an excerpt from an article on Joomla and Drupal differences. You can continue
Disclaimer: I am a marketing manager at CMS2CMS.