Battery life speed consistency optional rf transmitter feedneck strength
Weight, looks (to some people) price size
Well i picked up this loader in febuary 2008 and i havent changed the batteries since then. and the loader will feed up to 50 bps with the rf sync so if you happen to have an sl74 or sl8r ego then you can max out the rof with this loader.
although it sits really far back the loader still is quite comfortable to have on my guns. before you buy it make sure what it looks like on your gun before you purchase it though. because it looks great on my alien interceptor but not too great on my intimidator.