A warehouse sweat probably won't blow you away right away. Modern mass produced sweatshirts from Champion and similar brands are not bad at imitating a quality feeling out of the box, compared to modern denim which doesn't feel much like real denim at all. I bought a Champion sweat last year for a football game and it feels great in the hand, not that different from a 401. The best qualities of warehouse's sweats mostly come out over time by allowing the garment to gracefully age. The sweat will hold its shape, resist pilling and tearing, the brushed interior holds its structure and continues to feel comfortable against the skin, and it will fade attractively along its seams. You have to love wearing it long enough for it to 'pay off' though.
edit: I own a 403, a 450 and a 409. Agree with you that the pointy hoods on a lot of loopwheeled hoodies are unfortunate... obviously a different connotation in jp.