You should first know how complex your business or project is and what is its basic structure and requirement as this will help you better understand where one CMS may be better than the other.
When your website asks for creating multiple pages ordered in a hierarchy following a consistent style and ability to effortlessly create new pages, then Joomla will address your requirements.
On the other hand, Drupal outshines Joomla in delivering more multifaceted content connections.
It excels in creating a complex website with particular types of content appearing in a diverse manner and it also provides access control of authoring pages.
Although both CMS offer highly proficient services on an individual basis, it is necessary to deeply analyze them for a better comparison.
Joomla and Drupal website development serve to two slightly different markets.
Small and medium business owners prefer using Joomla because it is easier to customize.
Joomla developers find prompt online support and there are plenty of themes available.
Medium to large businesses require complex marketing and eCommerce solutions to help control their functionality that is better addressed by the Drupal community.
Though you can expect to find somehow the same functionality in Joomla as well, probably it has not reached the level of maturity required at huge enterprise level.
Your content management system cannot work separately; it has a network and is integrated with a number of extensions for advertisement, marketing, sales, and more; so you don't have to construct your required functionality from scratch and your plug and play with the extensions.
Joomla and Drupal both differ in terms of configuration of extensions and their customization.
Joomla is more manageable because its extensions are easily customizable whereas Drupal extensions are complex to configure and customize and you cannot easily add them to templates.
Drupal is less flexible and extensions are customizable only to meet specific needs of its users so it is important to choose the right extensions when working with Drupal.
When we talk about support and maintenance, both Joomla and Drupal website development offer great collaborative communities.
Drupal consists of 650,000 plus active users in its database and this number is on the increase.
The distinguishing characteristic of Drupal community members is that they talk about the code they use, and this is what we miss in other developer forums.
Joomla also offers very helpful community support system but it works in a different way.
Last but not least, we should see which of these two CMS, offers a better solution for eCommerce.
Basically, you need two things in a perfect eCommerce business website: flexibility and analytics.
We can safely say that Drupal and Joomla are not fully functioning feature-rich eCommerce platforms.
We don't find highly sophisticated eCommerce tools and options as we find in Magento CMS, but yes, we can customize both Drupal and Joomla to convert or extend into an effective eCommerce platform.
So whether you use Joomla or Drupal, you'll have their pros and cons, but you can customize the CMS you choose to build your dream website.