I got this one:
https://www.amazon.com/gp/product/B0..._title_o02_s00
and it's been just fine. Sleeps properly, doesn't smell, fits the device correctly. The magnets could be a bit stronger but I'm coming from a Kindle Voyage whose case was nearly perfect.
Personally I prefer the origami case because there are times you just need a stand and propping up the reader just isn't practical.