It's definitely worth it. I download quite a bit each month and having the ability to grab whatever I want (videos, bulk image packs, etc..) at the maximum connection speed (6mbit in my case) is well worth $14 a month. I subscribed to a usenet provider about 3 weeks ago (previously using torrents) and there is no going back for me.
As for newzbin, I wouldn't pay for a subscription simply because (as many have said) there are lots of nzb community sites that openly share and require no payment, such as this one .
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