I have a much loved pair of Bose QC15's, which are now around 10 years old. The zipper on the Bose case failed due to simple old-age, so I needed a replacement case. I was attracted to the Esimen case because it looked great, with a similar look to the current Bose design. Unfortunately, a pair of QC15's won't fit into the case.
It's basically identical to the official bose one however it doesn't have the sleeve on the inside which doesn't bother me. The materials don't feel as nice as the original but it's half the price and I see lots of people saying that the zip breaks on the official bose one anyway.
If you lost your original case then I'd suggest this one over the official replacement. It's a lot cheaper and does the same thing.