I'm a scratch DJ (or conversely: I'm a mix DJ) - what stylus should I choose?

Traditionally, scratch DJs prefer spherical styli, as they preserve more of the groove over repeated backcueing and scratching.  In theory, there is little difference between the tracking capabilities of an elliptical stylus versus a spherical stylus.  Mix DJs will benefit from either stylus type, and many choose elliptical based strictly on fidelity reasons.  However, there is no absolute rule on choosing a stylus - many mix DJs still use sphericals, and some scratch DJs are actually using ellipticals (including Ortofon endorsee DJ Netik, DMC World Champion).  One thing is for sure - if you choose to use an elliptical stylus, you should take care to not apply too much tracking weight, as it will prematurely cause unnecessary wear.