Evaluating both FF ad SD, they seems to have different strengths and weakness.Both have scripting capabilities (FF in LUA, SD in Python), both are node based, with a vast library of pre-made textures (free in case of FF).SD appear to be more streamlined in managing real world images to create materials, FF is probably more…
From what I have read and a bit tested with their trial, comes down to Filter Forge or Substance Designer. All the others (Quixel Mixer, Substance Alchemist, etc) are not scriptable nor node based. Dind't know if I miss some other app worth considering. Problem for FF is didn't play well with current Affinity Photo…
One of the major advantages of designer is it's place as a pipeline management tool - this is overlooked by most small operations as its just not that important to them but if you're proposing to build a massive library it may well be a consideration. Where designer's weaknesses lie are that you cannot develop your own…