I'd say a simple declaration "I'm using XXX" is very good indication, and it's easy for the user to enter

But not very informative. What are you using it for? On what platform? etc etc etc. Take the time, and tell them why you like it, and whats so good about it.

And also there can be huge differences between modules that are both rated as 5 stars, a usage number is probably a better indication.

Another reason why you should be more descriptive in your rating. Why did you rate it five stars? Personally, I would rather hear specifics, than see numbers.