When it comes to almost any web site that is more complex than one-person blog, drupal is my tool of choice.
This confidence started in late 2007, when my company decided to migrate its largest client sites from the self-developed CMS to something else.
Sincerely, the task was tough. About 3 thousand pages in 8 languages, several hundreds of page templates, endless code snippets residing in places you won't imagine in a sober mood... Think of 8 years of constant development performed by always changing team members, and you'll get the point.
Now, when I think of the fact that in 3 months we successfully relaunched English (heaviest) site on drupal, it seems unbelievable.
Yes, further steps were harder, and complete migration process, including all brands and all languages, took more than 2 years, but this initial success had given clear benefits of migration:
We launched our first site almost immediately after Drupal 6.0 release. As a result, some of contributed modules we needed did not have 6.x version
My task in migration project was to adapt existing modules to D6 API. I had to overcome curtain misunderstanding and even pressure from the company management, but all changes that I've done were committed back to the community.
Obligation to commit changes back to the community has naturally led to adoption of coding standards inside the company, and added discipline even to the private parts of code, i.e. modules that will never leave the company.
Today, I feel as a community member, and this already has no relation to the company I'm working at
Find the list of my drupal contributions here