Summary: I am using a 4TB version - very nice design and great performance. The speeds are about 170 MB/s for read and write. I am giving this disk a 3 stars only because of the loud fan - it is crazy how loud this thing is!
Summary: I purchased this drive to use as an external boot drive for my iMac. I installed all of my apps and operating system on it intending to increase the speed of my system. It was a success. My system is quite a bit faster than with the internal spinning drive due to the thunderbolt connection and the fast Solid State Drive. Be aware that this drive is two 250 gb drives and not one 500gb.