I have only used it once, but the Newer Technology eSATA to USB 3.0 adapter works very well.
Recently, I had to download over 300GB of video files, using my late 2011 17" MacBook Pro. I was using the Sonnet Tempo SATA Pro Express 34 card. One eSATA port was hooked up to a flash memory reader and the second port went to a CalDigit A/V USB 3.0 drive. The eSATA cable was plugged into the Newer Tech eSATA to USB 3 puck and worked like a charm. No errors and no crashes.
I had to buy a USB 3 hard drive, due to the lmited stock of the store I was at. Knowing I had a pair of these adapters in my computer kit, I got the USB 3 drive and rolled the dice, since I had never tested them.
The offload went smoothly and I was very happy with the way everything went.
My only complaint is that the one cable supplied is just the flat USB 1.0 style. They should also include the half round, or dome style USB 2.0 cable as well. One of the two hard drives that I bought had the dome shaped USB 2.0 style connector, but no cable (!). I was able to dig up a USB 2 dome style cable and that seemed to work fine. Offload times were consistent with the other drive using the eSATA cable.