A number of reasons were provided in this thread:

20 Dec.
>Plasticity is the only one that started out by blatantly plagiarizing my work.

22 Dec.
>Well it's in an area that I find particularly irritating - I don't like it when I see poorly designed UX being praised. And especially when it is being marketed as good UX.

23 Dec.
>If you're going to copy my stuff, why not do a proper job of it?

25 Dec.
>I guess I should explain that the original thing that pissed me off enough to start this thread was someone posting links to Plasticity advertising affiliate coupon codes after having been warned not to do that.

FWIW, I really wish that this thread had existed when I was first researching Plasticity --- I'd've bought MOI instead --- will finally be making that purchase once I've got PayPal funds lined up .

As far as marketing goes, I've always thought that the video which Naomi Wu did was a great start, and am saddened for many reasons that that was not followed up on --- that said, I did watch (and plan to re-watch) the YouTube series: Tom Meeks - 3D design for fun and life / Noun and Verb method --- perhaps an updated version of that could be done for v5?

Or just put out a video noting that if you find Blender difficulty to use, Plasticity will be too and to instead try MOI?