I do not agree with the review from jothik. You CAN add other registration fields which you define in the backend.
You CAN get a brand free version if you buy the PRO version.
There are a great deal of plugins to other components which is great. Instead of making their own components they just interact with already great components.
It is correct there is no CAPTHCA at the moment but you can enable Terms & Conditions so user have to check this field.
All in all a very great component that impressed me very deep first time I explored it. But you have to spend some time on it to make it "your best friend" because of all the options you have.