Slicethepie does pay but it is not worth it, below is a quote from their front page. Whatever you do, don’t slice that pie.
Influence what gets played on radio Discover tomorrow’s hits today Get paid to review music $1,228,318 earned for 11,045,448 reviews
I have used Slice the pie service and believe me, it is designed to maximize revenue for them and not you. Steer clear of this service. I have reviewed $10 pay worth of music which took me a long time to do actually. They only pay about .05 a review. The reason why I feel this service should be avoided is because they will give you a warning saying that your review are not “constructive”, they love the word constructive as it gives them an excuse to deny you pay. You can make an honest review about any music and even use different words for that review, but they will still come back at you with saying that your review is not “constructive”. After the first “non-constructive review” warning you get, they basically have the power to deny your review anytime afterwards for any reason.