there was a thread on this not too long ago...yesterday, in fact. You could probably get your answer by searching the forums.
But to answer your question, I read somewhere that the UR pulley set has shown to make more hp than the AEM
kit (don't ask me where I got that from, because I can't remember the source.) The crank pulley is where you are going to make the majority of your power in a pulley set. AEM
doesn't have a crank pulley. UR does. Hope this helps.