It is the best tool to identify the good and bad requesters in Mturk. Mturk is the mixed market place of good and bad requesters. OK I will tell what I mean by good and bad reqesters.
Good Requesters: Who will pay for your quality works and if they are satisfied will give more and more HITs to do for you and too they will put some scores to value your work and will screen you from doing bad quality works. You will get good payments from them and if you are lucky then will get some good bonus from them too. Also note that they can reject your task if you not followed their instructions carefully while doing the HITs.
Bad Requesters : They will steal your work and will reject your tasks without any reason and may or may not tell some bad comments that is not related to your HIT works.