i have one of those on my key ring (lost the cap first couple days). don't believe the claims on it for a second. i've never gotten over 180MB/s sustained writes. i tried it because i was curious first on my 3x1TB 840 EVO array, then on my SM951 M.2 SSD, and both produced roughly the same speeds ~180MB/s. tested a bunch of random data, music, movie files, etc.
it also looks like crap physically now, as the paint chips off really easily and you're left with a peppered looking, rather LARGE USB stick. they also get very hot just being plugged in to a USB port (even USB2) whether you're copying to it or not.
i've been using it for maybe 6 months? i can't remember.. i got it when they were being listed at $120 for the 120GB and i use it to move large downloads home all the time (i live out in the boonies and limited to my lonely bonded T1s, so easier to do big downloads at work). i've done a tone of rewriting and never had an issue. when you plug it in to your PC, it is not detected as a USB drive, it is detected as an external HDD/SSD/whatever drive.