Have anyone actually considered drawing optical sizes for web use on a strict pixel grid? I'm not talking about pixel fonts, rather just making sure all vertical and horizontal metrics plus stem weights fit full pixels at a specific size?
Poor? There are no deltas. This was to prove the qualities of a "hinted MM-GX-Superpolator font". After viewers became aware of the clarity in early proofs, they would soon start to complain the originals were too light, or too dark. So all of the possible weights of each size, more or less are cut on the same widths. Thus, yes... the lighter ones are airy, and the darker ones are pushing their widths. But the general idea is that either you, your topic or your rendering environment have to be pretty extreme to want the extreme weights in these designs for text or other small sizes.
Cheers!

This is a sample of Elementar, a flexible bitmap font system I have been working on since 2003. More info about it here.
Captured from web.archive.org on 9 Apr 2010. view this capture