Originally Posted by
Aruran.
Well to be fair I was reading Ultimate Spider-Man first in 2002 and only started Amazing from 2012 onward.
But I would say Gwen's death is more impactful, because it affects both Peter and Spider-Man. The marriage only affects Peter, which is still big.
Gwen's death is probably the 2nd most defining moment in Peter's life, cause it's really the moment when he stops be a kid and has to grow up. His marriage to MJ doesn't change how Spider-Man operates, it only changes Peter.
Mary Jane is the more important character out of the two, but Gwen is up there because of what had happen to her.