Boris, I do love your posts! I agree--the Dutch collection of tiaras is not necessarily the most pleasing--we do need to remember though, the time period in which they were created, and they are, in their own right, masterpieces of craftmanship.
That being said, I think they are generally overdone and look as if they may well induce headaches! The sapphire tiara has always looked painful to me. The Mellerio ruby tiara, well, I've never cared for it. It reminds me of garland on a Christmas tree--but, I DO love the necklace. It is beautiful. That ruby peacock thing just confuses me--the emerald tiara looks like a spear rising up out of the head and thusly, I don't love it. It's off, there is too much in the middle and the whole thing looks oddly shaped.
I do like the Laurel wreath tiara--it's lovely, and simple. And, while it is true that the diamond bandeau tiara is indeed nothing more than a necklace on a tiara frame---it's simplicity won me completely over because all the other tiaras are so overdone. And, Maxima outshines all jewels anyway, so the simpler the better. There is no way a tiara can compete with her.