The build quality is good, however, there are a few flaws.
The Switch can fit VERY snug into the compartment to the point where you need to actually push it into it. It won't be popping out by itself. There is a small pull tab that you use to pop the switch out, if you put the switch in with the pull tab over instead of under, you will most likely need to flex the case to get the switch out. You will need to take care when using the pull tab because it's possible to launch the switch if you're not paying attention.
The game compartment slots are of good quality, however, both of my game slot flaps have the left side shorter than the right side. The games still fit into the left slots so it isn't a problem, it's just a small warning if you dislike uneven aspects or believe they show cheap quality control (Far left side measures 280mm, far right side measures 310mm, and the three in the middle measure 330mm, it's very noticeable).
The game holders themselves are decent and the cartridges fit tightly into them. The obvious flaw is that you cannot see the cartridge arts which may be a problem if you have a good amount of them but you can get away with putting them about 3/4 of the way in so that you can still see a small portion of the art, they still won't be falling out.
However, the top row of the game holders are too high up so you will have difficulty getting games in and out. Closing the case will also force the cartridges all the way down. Just something to keep in mind if you have more than 10 cartridges to carry or you are thinking of choosing this case because you need to hold ~20 cartridges.
The bottom portion of the flaps have a soft material that won't be scratching your screen, nor will your cartridges scratch from sliding in and out.
The top compartment for accessories is spacious, I do not have a spare pair of joy-cons so I had to test by using one of my joy-cons. You need to place them at the ends of the accessories compartment so that they do not press down on the game holder flaps, otherwise, you will need to put a lot of force into closing the case which I recommend against since doing so will likely damage your joy-cons' sticks or your cartridges. Wrist straps fit without a problem. Joy-con grip(s) will not fit.
The accessories zipper is annoying because when you close the case, the zipper will be hanging down and often stop the case from closing (It catches on the arrow buttons) unless you close it at an angle or have a finger hold it down while closing.
The outer part of the case gets dirty very easily so be prepared to do a lot of wiping but it doesn't warp or bend much under pressure.
The zipper for the case itself is hard to move and requires a good amount of force. You will most likely always be holding it against your chest when closing the case.
For $13 (AUD), I'd say it's worth it, the inner material is great and everything fits tight and nothing should be falling out. The only real reason I'd recommend against buying this is if you need it to hold a lot of game cartridges because the top row of both flaps are too high up, you have about 1cm of space to get them in and out.
The card it came with says there's a 30 day, any reason, money-back guarantee so if your order has any obvious issues, contact the seller.