I asked myself the same question when I bought it. I think the Micasa's wood is of better quality (it may even be a real wood veneer).
The Seaford clearly has a "wood effect" resin veneer, seen up close (but with the grain and all).

At a normal distance it looks fine. Its only faults are the assembly plan and it was a bit over-packaged, a lot of plastic for nothing (sent from Holland as I recall). But it looks very good and there's nothing tricky about building it.

I think it's the type of wood. This model (same placement of the shelves) has been available at almost every furniture shop for several years. They all look exactly the same