Amazon Review Groups || Good idea?

Does anyone have some experience with Amazon review groups? They seem kinda fun... get paid to write a review and get the item for free (sometimes). However, I do THINK that is against the rules of Amazon-- so I guess my question is two fold...

1) Do you do it? Why? Is it worth it?

2) Is there a way to do it and also remain in the bounds of the terms of Amazon? (ie not getting a commission for the review, just getting the item for free?, etc.)