Well, this is really a matter of semantics.

There is definitely a difference. Some people would define this difference as meaning "Harder".

Then again, they are harder to fly than say, a trainer. So going from a trainer to a bipe would mean:

1, It's harder, and

2, It's different - thereby making it even harder

It's also worth noting that different bipes fly differently, so where one may have a lot of extra drag due to the extra wing, the drag in another may be almost unnoticeable.

But one of the biggest factors is orientation - You know those times when you can't tell if the plane is coming toward you or going away? Well with a Bipe, that seems to happen a lot, so if you have troublw with that, you'll have even more trouble with it when you're flying a bipe.

So I won't agree or disagree with the article, but I will say that some people won't find it harder, while others will.