Have ordered from Taiwan based devilcase, read from the Xperia sub-reddit that the cases are of good quality, there's free shipping till today for orders above 35 USD.
Got the crystal case from their US online store during black friday sale for free shipping. Can't say I'm too impressed for the price they are charging. The back of the case is about as glossy as the 5 III so it's nearly as slippery and fingerprint magnet as the phone itself. Mine already had macro scratches after a few days.. And I'm not sure if it's just bad tolerance, but mine fits really tight, so god forbid if I need to take it off. I legit fear I might scratch the phone when I took it off once. To be fair, it does feels pretty robust on the hand if I exclude the cosmetic aspect.
The glossy screen protector feels good to touch, but it seems like the one I got is about 1-2mm short on the width? The left side
seems to align just nice but the right side have a hairline of pixels lighting up just outside of the border of the screen protector. What annoyed me the most is how the screen protector is pasted on a plastic back that extends a healthy amount beyond the edge of the screen protector itself. So I couldn't do the good old "'door hinge" trick with two scotch tape to ensure best fit before I remove the protective layer off the screen protector.
Tl;dr: avoid if you're OCD on the looks, else they will serve you well. I kinda expect more for it's price tho