> Pitman and Gregg are Featural (in Sampson's sense). I suppose this
> one is similar.

It's not really, and neither are Gregg and Pitman similar to each
other. I've done some research about stenography, only in the web, not
much, but enough to see that there's an amazing variation between
different types of stenography. I've found three very different types,
but there may be more. The main differences are in vowel notation.

Some systems, the best known of which is Pitman's, don't have letters
for the vowels, but only diachritic markers. They are ommitted whenever
possible, and the first vowel of a word is marked in a different way:
by the position of the word over, on or under the line.

Other systems, as the widely used Gregg shorthand, have letters for all
sounds, for consonants as for vowels.

Others, as the Gabelsberger system and its decendents, mark the vowels
by the kind of linking between two consonants.