In PSUs, I find that true. A bad psu might last a week or two then crap out on you.
With motherboards, I find they will almost always last a year or two regardless of how cheap/crappy they are. They will lack features, but they won't just stop working for a while. I've built prolly 10 systems for myself and others using ECS motherboards and only one is not working, and it stopped working 4 years after being built. And ECS is about as cheap as motherboards go.
Go open up a computer they sell at wal-mart. Half of them are ECS motherboards, and they almost always work for several years.