I have seen poor results from Powerslots in the past (warped in a very short time after some entertaining driving).
Ive had good personal experience with slotted Stoptech rotors (lots of agressive driving and no warping or cracking), but Im not sure if they are available for our cars.
Even factory drilled rotors can crack, ever look at the massive rotors on Lambos? Ive seen a few with a lot of hairlines.
It has to do with the way the rotors are made, the actual drilling process into a blank rotor is what will cause a rotor to crack. Some manufacturers use a different "drilling" method.
Its best to buy a good name brand rotor rather than spending the money on holes and slots. Ive had good luck with blanks before, they were a reputable brand. Ive seen drilled and slotted rotors go bad in no time.