General consensus on Cube4you is that...
Type-A's are the best,
Type B's are the worst (and yeah, they're really bad, same amount of lockups as a store-bought cube), and
Type-C's are pretty good (some say the Blue Type-C is as good as the White Type-A)
As for the new Type-D, I have quite a few (we can buy them locally here for almost half the price), and I'd say it's as good as a Type-A (very smooth, almost no lock-ups), except it doesn't pop (almost). So it's a bit better.
The only problem with the Type-D's is that you can't really tighten the screw so much, so its tightest setting is a bit loose. Not a problem if you like your cube a bit loose, but if you like a bit of tightness in your cube, well, this isn't the cube you'd want.
As for Yu's storebought cube... you can buy a Rubik's Assembly off the shelf in Japan, so that's actually not the rivet-type Rubik's cube, it's also a DIY, and much a better one than the C4Y's at that.