I'm a bit heavy handed, so maybe I'm not the best to ask about that, but I've barely noticed that the spacebar is even heavier. It does definitely have a bit more resistance, but it doesn't bother me whatsoever.
And as far as the build quality goes, it is a full plastic keyboard, but I wouldn't say that makes the build quality poor. It has less flex than my KBC Poker II, and only slightly more than my corsair k70. Keycaps are really nice...