If your looking to buy new, the only thing that should really sway your decision is the warranty associated with it.
My sister had a WD in a Gateway she bought from a store and it died 4 months later. The place she bought it from wouldn't do anything for her because they only had a 90 day warranty on what they sell, but she knew this when she bought it. But Gateway was also supposed to have a one year warranty on their stuff as well as WD having a 3 year warranty.
And that was all well and good until she found out that the computer was built just over 3 years ago and the warranty had run out.
She wound up buying a Seagate that now has a 5 year warranty on it.
So no matter what your looking at buying, check the warranty, the longer the better.