I recently saw a video on YouTube where the race chairman claimed that the Midwinter Marathon was, after Athens, the second most difficult marathon in the world on account of the deceptive inclines. I've since had a reaction from him via Twitter (albeit rather unclear) after I asked him what he based that opinion on and he admitted he'd made a mistake in what he said.
I spend a bit of time on a Dutch forum (please don't think that I'm Dutch) and have tried to gauge the reaction of people who have already run in Apeldoorn. Nobody said it was an absolute killer, but I have been told that there is a total incline of about 225 metres.