You get what you pay for with suspension.
Any cheap suspension seems to be hit & miss, some are good, some are awful - you just don't know until it arrives. They'll probably creak a lot initially until you grease them up properly, the ride will be very bouncy, harsh and uncomfortable, you may find it difficult to get them sitting level. However.....
For the money they are ok, you get the benefit of being able to set your height as high/low as you want and it improves the handling tenfold. Ultimately it depends on whether you want to slam the car or just a subtle drop because you may be better off with a spring/shock setup.