You asked about "the ones that say they can hold 200 chips, be shaken upsidedown, need no flips...etc."
I have three of them--
"How well do they preserve the chips?"
Don't have any evidence that they have any adverse effects but I know there are people on this board who sell them and they are better qualified to speak to this important issue.
"Is there contact between the chips?"
No
"How are the chips held in place?"
Friction--the slots are slightly smaller than the chips and the material stretches to allow the chip to enter the slot and still holds it firmly in place. They are absolutely truthful when they say you can turn them upside down, shake them, etc. and the chips stay in place.

I just ordered another one so I guess that tells you my view--

D.