Sorry but the problem DOES exist.
Indeed if you check on Apple System Profiler you'll see that the factory installed HDD as well as the ODD are both running at SATA 1.5 Gbps even being able to run at 3 Gbps.
I put a new hard disk and after transfering a couple of gigabytes it stuck.
I booted on Linux and tried the same, after 5 seconds of transfer the bus reset and the Linux kernel instructed the controller to link at 1.5Gbps, then it transfered 320 Gb of data without a single fail.
I downloaded the drive's tool from manufacturer (Samsung), run it on a PC and forced the disk to link always at 1.5 Gbps and now it works flawlessly on the MacBook Pro.
This is a known problem, that's why Apple drives come forced to 1.5 Gbps.
Regards,
Natalia Portillo
Apple Certified Macintosh Technician