These are cheap monitoring headphones that just about do their job. They sit on your head, provide the sound you need for monitoring and nothing else.
The build quality is fine. It won't just fall apart when you use them. Comfort is the main issue, as with most headphones in this price bracket. The plastic padding and clamping pressure will make these very fatiguing over long periods of time. I pity the person that has these headphones for monitoring and mixing, activities that can last for hours on end. You will get sick of them long before you've finished your work.
Sound wise, these are plenty revealing for the price bracket they're in. Again, I cannot recommend these as the only pair of headphones you have, even if the other ones you have aren't built for monitoring. These just won't cut it.
In conclusion, these are cheap monitoring headphones built to the spec of good cheap monitoring headphones. Keep your expectations in check and you mightn't be disappointed.