Ever since osCon08 we've been getting this question a lot. We even got it from the Drupal volunteers who essentially asked ‘with Drupal in the world, why would you even build another CMS?' I think the answer is pretty obvious from just watching the screencast or playing with the demo on concrete5.org, but here's some thoughts I've had with people via email recently:
We are thinking of using Drupal as a basis for a new portal/application server website and became aware of Concrete5.
I would be interested in a brief chat with someone regarding your views of the pros and cons of the two applications, and about some custom work and support for our projects if we decide to base it on Concrete5.
I think c5 is better than Drupal for any number of reasons:
1) It was a successful commercial product for years, so we were paid to throw bad ideas out. Most projects that are open source from the get go have to worry as much about politics as programming. We had the leisure of being paid to make mistakes and fix them for 5 years before giving the core framework away.
2) It actually does what you'd expect out of the box. Look we don't have thousands of developers working with it yet (I think?) but what's in c5 actually works well, it all looks and behaves as one, and it's going to let you solve 90% of the problems you're likely to run into building the average website. You don't have to be an expert in which module breaks which other modules in order to get a site built.
3) It's just as flexible and stable (arguably a good deal more so – but I'm not a Drupal expert and am obviously biased). I can say from my experiences and everything we've been hearing from the community it's a good deal easier and more enjoyable for the end site owner to use. That means a lot when you're waiting for a check – we know.
I'm sure there are a good many more reasons why so many people and shops are taking their Drupal powered sites and rebuilding them in c5, we'd love to hear them here. Is it just the UI, or is the development environment appealing as well? Is it the page types/themes architecture or just that permissions are bundled and you don't have to deal with thousands of competing modules? Is it our massively complete and impressive developer documentation?
We know a lot of people already prefer c5, reach out and tell us what we've done right and what we still need to work on. .. oh, and what you hate about Drupal, so we don't end up making the same mistakes as this grows.