Yeah, I did not agree with his mentallity about nearly always losing to IG and nids. In most games I've played against nids, either it was a draw, or it was a victorious slaughter in my favor (splinter cannons rip these armies to shreds).
If anything, I have the most trouble against the Necrons (an army that he said is your easiest match-up). The fact that necrons can teleport out of hth and leave you wych squads in the open (combined with the fact that it is ridiculously hard for DE to take down a monolith), makes playing against the necron a living hell for me.
Also, yes, the glaring error about being able to use two-handed weapons on jetbikes (this was actually pretty much what his strategy was based on).
Also, I disagreed with his statement that Archons are a waste of points. They are only 25 points more, and i find the increase to attacks, initiative, WS, leadership, and wounds to be invaluable. Besides, why not (providing of course that you have the extra 25 points to spare), just purchase and archon AND a dracon (as opposed to just two dracons).
While he had some valid points to make about the incubi being incredibly vulnerable if their raider is downed, I still find them to be a vital unit in my army, and they are the only reason that I don't use a wych army (i'd hate to have to go to battle without my incubi). This opinion of course DOES differ from player to player.
All in all, regardless of my critiques and dislikes on some aspects, he made some very useful remarks about deployment, formations, and tactics (I actually DID learn a few new things that I think will make a difference in my playing). Mostly, I'm just glad to see that the Dark Eldar are getting some well-deserved press in the WD, and it makes me even more anxious for the release of the new eldar codex sometime next year.