Originally Posted by Drithius
I haven't played Rift, but, from what I've read, the rifts there are pretty basic events that don't change over time. In contrast, dynamic events actually change the world in GW2. For example, if you fail to protect a water supply during one event, it leads to another event that has noxious fumes coming up from the same water supply. Fail to defend a town, and you are in for one helluva tough fight taking it back from the enemy.
Bear in mind that all of these events reward sizable chunks of experience at the end. So fun interactive content + rewards = a win in my book.