I doubt they are any good. Think about it - your seat is probably the most important part of the car as far as your safety in an accident. Good aftermarket seats like Sparco, Recaro, etc. are crash tested to make sure they are even better than stock seats in an accident.
Trust me, anyone can make a mold and produce carbon fiber seats that look cool. The name brand seats are more expensive for a reason - they are designed and tested for safety and that costs money. You get what you pay for.