I had 2 keys USB2, an 8GB that allowed me to copy files (5.5 GB of videos) to 10.7 MB / s, another 32 GB but the maximum speed is 3.5 MB / s. I bought this key to have a big storage with reasonable speed.
It is thin enough not to interfere with another USB device. She instantly recognized USB2 and USB3, and by my Samsung TV.
The observed transfer speed (from PC to the key, Windows 7) is 26.6 MB / s USB2 and 33.5 MB / s USB3. I do not have USB3 else that allows me to compare its performance, but in any case this meets my need for a low price.
Provided that it lasts as long as my 8 GB that has never been a problem, it is an excellent value for money (20 free promo and delivered in 48 hours by Amazon).
I am therefore pleased by the key, and of course by the excellent Amazon service.
Update on 14/10/2012:
I reinstalled my motherboard using the right USB3 drivers. I note that the rate is now above 85 MB / s. I confirm that this key keeps its promises, the flow is near the eSATA.