No I would say keep them. At the end of the day a hard drive is a hard drive. If you got a great deal I'd stick with it. They are quiet, and low energy, and have a decent warranty. That probably makes up for a lot in your situation. And gains you might make in exchanging them isn't worth the hassle. You have nothing to worry about. Build your HTPC and enjoy it for years
My rant is mostly about how WD marketing pushes these drives (at higher prices) and they really are not even designed for a PC or HTPC. They market them as more reliable and slap an extra year warranty on them suggesting to consumers they are premium, but really they are identical to green drives in parts and only changes are the firmware to make them suitable for NAS appliance boxes. It gives people the wrong impression of these drives, and WD doesn't provide enough intelligent alternatives cheaper for the traditional hard drive markets. It just bugs me. I see it as WD misleading consumers to buy a certain HDD so they can rape an extra $20 of margin from them.
Hitachi, Toshiba, and Seagate all offer traditional HDDs in 3TB sizes for about $100. Where is WD? Hitachi and Seagate have 4TB low powered drives under $150 often too. None of them are NAS specific either, they are just simple all purpose hard drives.