With the ordered me HDD from Toshiba everything works fine: no vibration, no audible noise, almost no heat generation. Data transfer on the iMac with Time Machine approximately 100 MB / s at 850 GB backup. For me, everything was perfect. The entire system should be extended to me at a later date with an additional housing, as stackable. The appearance fits well with the Imac .... anyway always better than the various plastic HDD. Whether the perceived quality stops at the end, what it promises to be seen ... but I'm in this regard due to the first experiences very optimistic.