I'm personally a fan of the pattern and think that the (although somewhat annoying but also minor) overhead of maintaining interfaces is worth the cost of having a consistent scheme of how things get plugged together. Also I don't think it's too convoluted to follow now that I have experience with the pattern and workflow.
Anyway what do you guys think about the practice? What do you find are the pros and cons? Do you have any run ins with people new to it? How do they feel about it? etc..etc