I don't have any of these, but have most other available dx's.
http://nerdist.com/this-d120-is-the-largest-mathematically-fair-die-possibl e/
I need a bit more to convince me on the mathematically-fair aspect.
So by mathematically fair, do they mean that the numbers are spread evenly so that each opposite pairing equals maximum number +1 and numbers are clustered evenly so there are no concentrations of high or low numbers near any kind of facing?
Because I don't see why 120 is the highest possible number of faces there.
Anyway, for a d120 you can always just roll a d12 and a d10 together and add them using the percentile die principle. Similarly you can achieve d30, d40, d60, d80, and d200
And check out the d20 that dates back to 320 BC-30 BC
Oldest Known d20
I need one of these. Now.
Because I don't see why 120 is the highest possible number of faces there.
Well, the Disdyakis triacontahedron (i.e. the d120) is the largest Catalan or Archimedean Solid, so you're not going to get something that looks like a traditional die that's got more faces. This is basically a graph theory proof that's not very interesting.
You can make dice from bipyramids or trapezohedra with as many faces as you want, the problem would be that (aside from issues building the thing) the trapezohedral d1000 would roll for a long, long time before it stopped on any given face, so it would be impractical.
This, however, is also pretty impractical. But I imagine people will buy it for some reason anyway.
I'd buy it for the novelty factor alone. I love dice and it would just be a neat addition to my collection.