1) Python documentation is significantly better than the equivalent Ruby documentation. If you want to learn Python or look up a function, you go to the Python website and you're done. For Ruby, you can find a large number of third party tutorials and published books… The same comments apply for Django compared to Rails.

2) Based on relatively little experience but I get the distinct impression that Rails is willing to make seriously backwards incompatible changes for relatively minor reasons. The few Rails developers I've had a chance to talk to personally also aren't too thrilled about this aspect.

3) Ruby makes much heavier use of magical function names. If you know what they are, that's all fine and good. If you need to consult documentation or are trying to link it back to how it was created however…

Anyway, I'm not sure what he's talking about exactly when he says “rack apps.” Whether he literally means microframeworks like Sinatra, or Rails own internal microframework, Metal. Both are very cool, but have sort of niche appeal.

If he's talking about Engines, then let me say +1. It doesn't quite get us to Djangoland, but it comes close.

The bottom line is it's good to see these frameworks growing and learning from one another… migrations to Django; engines to Rails.