Although I understand the point, I think it's more accurate to describe Groovy as the "Ruby" of Java rather than Python. Groovy's philosophy and syntax are all very Ruby-like, while many things about it are completely orthogonal to the same in Python.

Where Python is usually trying to have just "one way" to do things, Groovy offers you a million. Python actually share's much of Java's annoying desire to keep the default namespace clean and hence make you import modules to do just about anything useful. While Python puts simplicity and cleanliness on a pedestal, Groovy is unashamedly pragmatic, letting you do any dirty thing you feel like or need to do to get your job done.

In complete contradiction to Python's direction of eliminating it (eg: forcing brackets on print() statements) Groovy gives you incredible amounts of optional syntax - add semicolons? if you want ... or not ... except sometimes the syntax gets ambiguous they are required. Use brackets on your function calls? If you want ... or not ... except sometimes the syntax gets ambiguous, so they are required. The author didn't even mention optional static typing which not only enforces type correctness on parts of the code you apply it too, but dramatically speeds them up. So much freedom makes it easy for Groovy code to end up messy and unstructured compared to Python.

I'm currently in a situation where I switch between Groovy and Python coding on alternate days. I definitely prefer different things about each. Groovy definitely seems more powerful when I just need to get a simple job done. It is incredible what you can cram into a single line.

I hope Groovy continues to prosper, but I worry it's getting lost among the hype around more "sexy" languages. I think it's by far the best language for many jobs.