I've also heard others mention that HP from HPMoR is an unsufferable little twat, which I assume is the same attitude they would have if they were to read LW.

I also think that HJPEV is a unsufferable little twat / horrible little jerk, but I love LW and have donated hundreds of dollars to SIAI. And I've strongly recommended HPMOR itself even when I warn people it has something of a jerk for a protagonist. Why shouldn't I ? Is anyone disputing that he's much less nice than e.g. Hermione is, and he often treats other people with horribly bad manners? If he's not insufferable, who is actually suffering him other than Hermione (who has also had to punish him by not speaking to him for a week) or Draco (who found him so insufferable in occasion that he locked him up and Gom-Jabbared him...)