Haven't had the chance to handle the GP Paps or Nemesis, but I do own a pulse!
Highest quality Pinoy mod I've ever owned. [have owned several..2 sentinel, titan, nzonic v1, nzonic v2, Launcher v2]
Threads are super smooth and sits incredibly flush and stylish with the
kayfun.
My only "gripe" would be that the button tilts a bit when standing up unlocked. Not enough to fall over [yet?], but enough to where I'm more comfortable locking it first.
Hits great and super compact.
I do only own the 18350 tube so no experience with the 500/650 modes.
Nemesis definitely has the hype between all you mentioned.