Fast and robust

21MB / s perhaps, but on a PC or racing machine with USB 3 (even if the key is in USB 2) converted to NTFS, which is not a good idea for USB stick because Windows for the NTFS file copy NTFS uses RAM as a buffer, one can even be surprised to a transfer rate of about 80MB / s, which is not true because after account, Windows will put considerable time to finalize the copy. From my side, the average speed is contacted 7MB / s (without PC beast), which is very correct for a USB stick, either NTFS, FAT32 or exFAT by (the total copy time is virtually identical for all 3 formats). I recommend you stay exFAT if you want to have good performance and if you want to upload files larger than 4GB (limited still to 16GB max) or stay in FAT32 (default key size, limited to 4GB per file) in order to enjoy maximum compatibility with other devices like a PS3 or connected to a LINUX or MAC system.
The key in itself seems very robust, but even with the valve connection remains open. Attention to what is behind in your pocket!
I always recommend for those looking for a robust drive with good transfer speed.