As someone who has done 4 years of Rails development and has recently switched to Django for new projects, I can tell you it would be worthwhile to learn both. Ruby and Rails are great most of the time, and the Ruby way of doing things is a great learning experience.
That said, I threw my hands up after running into multiple libraries duck punching (monkey patching) ActiveSupport into a mangled, conflicting mess one too many times. The open classes thing really is harmful, no matter what anyone tells you. It's a feature that, when used with care, can be very powerful...but the problem is in my experience it's not used with care very often in the Rails world.
I've heard Scala solves the issue with open classes by keeping things in context with the code that surrounds it, but I personally haven't verified it. Besides, that's not what you asked.
Here's a metaphor that I really feel holds true: Rubyists are magicians...Pythonistas are masons. If you have to rely on your own code only, then by all means delve as deep into magic as possible. However, if you have to rely on other's work, the mason's approach is much more intuitive, reliable, and safe.
That said, I threw my hands up after running into multiple libraries duck punching (monkey patching) ActiveSupport into a mangled, conflicting mess one too many times. The open classes thing really is harmful, no matter what anyone tells you. It's a feature that, when used with care, can be very powerful...but the problem is in my experience it's not used with care very often in the Rails world.
I've heard Scala solves the issue with open classes by keeping things in context with the code that surrounds it, but I personally haven't verified it. Besides, that's not what you asked.
Here's a metaphor that I really feel holds true: Rubyists are magicians...Pythonistas are masons. If you have to rely on your own code only, then by all means delve as deep into magic as possible. However, if you have to rely on other's work, the mason's approach is much more intuitive, reliable, and safe.