Jesse Farmer has a good article at 20Bits critiquing 4 Problems with Drupal. The problems that Jesse points out are very relevant and this is really worth reading if you are looking into Drupal. I don't agree with some of the conclusions and I will not be switching to Rails/MVC but Drupal is definitely defective even if it is very useful. From TFA:

I really don't mean to dump on Drupal so much. Well, ok, I do, but it's not out of spite. Part of it is that, as a developer, I find Drupal to be very unfriendly. I know exactly what I want to do and more often than not Drupal is a roadblock. Add to this the performance issues and I think anyone trying to use Drupal to design a medium-to-large sized interactive website should definitely take a second look.

It may be just a little bit ironic that I'm running DeveloperFriendly.com with such an unfriendly CMS but Drupal is currently serving me well. For the time being I will just enjoy the irony.