I tried it but as all above said, there was NO significant difference.
But there is a issue too, as i remember if you read their policy of using the service, they keep a track of what we did on internet (actually thats how they speed up web). So more you use more fast it will get as i think. But the problem is, if you are downloading copyright material (films, songs...) or any other illegal stuff, they have the evidence we did that. So " i think " it could be used against you

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So better think about that too if you are thinking to use it.