It's honestly hard to tell them apart, and I apologise if it's not clear in the article because I guess it wasn't really clear to me either.
What I can say for sure is: the more people in one area (for PVP, for city events, for world events, etc) the worse the frame-rate and the lag between input and result became, from half-a-second to a full second in some of the worst cases. In some of the WvW battles and in the final party at the end it was basically a slideshow.
When I was solo'ing quests the game was as playable as a normal MMO like WoW
or whathaveyou, and pretty much the same in small groups. The game defaulted my game to High on nearly all the settings and I had no trouble running at all until encountering large groups, but even then turning all the settings down/off made no difference. So I'm reasonably sure it's not a hardware issue (at least on my end).
All I can say for sure is in its present state, Arena's claim that this is going to be a valid esports title is just not going to hold up for Australians unless we get closer servers.
Perhaps the Ausgamers guy had a different experience to me, but it felt like there was, if nothing else, a bit of optimisation left to do in large-scale battles. I really wouldn't describe the network code as 'rock solid', unfortunately