I ordered this and I thought they were great. Nice weight d20 seemed exactly what I ordered.
I didn't really notice that the rest of the dice are slightly smaller than standard sizes of these dice until i just started a new campaign.
I guess it is my fault for not doing the research, although I don't see the dimensions on the page so I can't say i was cheated. That said, the size is important and it matters. These would be perfect if they weren't too small ...
the standard size for polyhedral dice should be
d4 ~15–16 mm edge (triangular faces)
d6 16 mm per edge (cube)
d8 ~16 mm between opposing faces
d10 ~16 mm diameter across
d10 ~16 mm diameter across
d12 ~16 mm diameter across
d20 ~16 mm diameter across
the size of these dice are not the standard values, aside from the d20.
TLDNR: The d20 is the standard size, but all the rest are mini dice