This is all anecdotal so probably not enough to be conclusive but I've noticed both a somewhat nootropic but definitely a significantly mood-enhancing effect from it.
Color were brighter after the first few days. Not psychedelic brighter but bluer blues, greener greens. What I felt was reminiscent of that child-like awe in experiences along with remembering instances of those awe-filled moments I had as a child.
Looking at the sky and watching the nature (which is something I hadn't been doing in years) made think "I'm lucky to be able to observe this". Looking at the sky and watching the way clouds move brought back flashbacks of probably the last time I had done that as a kid.
Very interesting chemical indeed. I believe it has a lot of potential.
After using up my supply, there was no withdrawal or crash. I guess the color enhancement went away gradually over a few months. However I could argue I got permanent memory enhancement from it. I have no data to support it but I became the kind of person that can remember the most obscure things and follow really long chains of connotations. And if you asked me, I wasn't like that before experimenting with NSI-189.
But that being said, I even tried Cerebrolysin months before that for nootropic exploration. So for all we know, the memory enhancement stems from that. In hindsight, I must have been very daring to have injected myself with peptides purified from pig brains. :)