The cable does increase transfer rates but by nowhere near the 10x advertised rate. I backed up my PC using the backup software that came pre-installed on the PC. The software makes an image of the PC's drive that, in this case, is about 70 GB compressed. I made two backups to the same Goflex drive on separate days using first the USB 2.0 cable and then the USB 3.0 upgrade. The resulting transfer rate increased from approximately 12MB/s using USB 2.0, to 31MB/s using USB 3.0. That is an improvement of about 2.5x. I've read that this has more to do with the limitations of the rest of the systems than it does with USB 3.0. Examples would include the transfer rates of the disk drives themselves, the software, and even the CPU. Overall, I'm happy; for not much more than twenty bucks I less than halved the time it takes to backup my PC. It's difficult to complain about that.
My only complaint with the cable is the fact that you cannot remove the cable from the adapter. This makes it impossible to fit the portable drive into its carrying case without removing the entire adapter. Then you have to store the adapter separately. If Seagate did that only to save money, boo to them; I would have gladly paid more for a removable cable. So for that, it gets 4 stars. Still, I'd call it a must-have upgrade for any Goflex USB 2.0 drive. I'll be buying one for my other drive.
Kudos to Seagate for the upgradable drive concept. That's a five star concept.
To put the whole thing into perspective: the original IBM PC XT came with a 10 MB drive. That was a mind boggling amount of space. It held all of your software and data. With today's 31 MB/s transfer rate, you could have transferred the entire contents of 3 of those drives in less than 1 second. That is awesome.