I feel Cowon Z2 is a really good DAP for the price and it takes some abuse. Initially there were hiccups (in the first 4 months of purchasing) like hot battery after a charge & heavy battery drainage even with the dap turned off. Thinking maybe it was due to a humid room (humidity would be at 74-80%), I purchased a humidifier (a year ago) and now everything keeps a great battery level even after weeks of the dap turned off. I have no problems what so ever with the Cowon.
A neat thing about the Cowon (or any other dap with a clear hard case) is if you purchase a clear hard case (came free with mine) and place the digizoid amp front light onto the back side of the Cowon, it illuminates at night. Works well the W4R. Also plays video clips from your digital camera when you get bored of music!