How can you tell between a dog sweater that is mass produced cheaper versus a high end handknit sweater? Is there even a difference? Check this out:
Cheap dog sweaters flop around at the back and don't hug the body. In the image above, look at the edging around the thighs, that red sweater corner will not stay on the dog and the sweater will easily flip back compared to the Bravehound sweater. Below, you can see how the black Halloween sweater back looks like a rectangle of fabric lays on the back instead of a form fitting knit.
Here below you can see the stomach panel isn't fitted and curved, it doesn't follow the line of the dog and doesn't keep the sweater in place with the grey sweater. The neckline is also much too wide.
The knit is thin and stretches out of shape easily, the yarn is low quality, feels like a cheap sweater and doesn't really keep the dog warm, especially if damp. I haven't found any other sweater outside of Bravehound that has a turtleneck that folds over.
Lastly, put the sweaters in a wash over and over. Good well made ones will bounce back into shape and last for years and years. Cheaper ones will stretch or break.