Works as described, will give a quick test of memory performance. Free version won't work with internal memory configured SD cards. I also compared it against doing it manually with a stop watch and its spot on. The Read performance, is Read to app or RAM memory which is fast than real world, its read to another storage device, which is written to and slows the actual transfer down. Would recommend to anyone wishing to test new SD cards to prove its performance or new hardware.
SD Card Test at Google Play market analyse