One thing to note - SATA cables don;t bend very easily; if there is slack, its best to twist the cable than bend it - otherwise it could break. This is especially important in cases with not much space, or external hard drive caddies.
Also, the power adapter is very short, which is OK because the power leads form the PSU should be plenty long enough anyway, but still worth mentioning.
The price of these units is very low - compare the cost of a SATA data cable in PCWorld!
The data cable is fine but the power converter cable is not well made.
The four pins are loose in the holder and move about. If all four pins are not lined up correctly to plug into the Moldex type power plug one or more of the pins is simply pushed out of the back of the adapter.
I eventually squeezed a tiny amount of silicone sealent into the back of the adapter and let it set overnight.