I do have a lot of the old palettes and only one of the new type. I must say I prefer the look of the new ones, they're shinier and sleeker

And the single ones have the window to look through. I was searching about the duo ones which was how I ended up in this thread, and I just ordered one with 2 15 inserts from eBay after having searched around on swap sites to no avail.( I live in Norway) I'm glad to see they've reduced the price since they first came out, but boy are eBay prices terrible. I don't remember the price they used to be at on the US site, but I remember thinking there was no way I'd change from the old ones at those prices.
Hopefully I won't have the problems some people have had with shadows falling out of the duo one, since half of them will be upside down. At least I have the inserts, that should solve some of it, right? I'll probably be getting some more single palettes next though, it's nice to have the little window and not worry about the falling out. I'll stay vigilant in the swapping communities. XD
I accumulated a bunch of mac pans some years ago when I first discovered swap/sell communities and found eyeshadows for cheap, sometimes even buying some filled palettes for cheap. I guess it's a fun little project I can do in the future(I'm in the process of moving) to take them all out, clean everything nicely and rearrrange them. The palettes become "dusty" over time, and my careless brother has also knocked some palettes off the shelves breaking some of the shadows