Are male Greys' better talkers...
From my own personal experience I would say no. Having had two males and one female, each one spoke absolutely beautifully.
Congo the male (had him for 7 years, only spoke a black language when I got him) Within a year he spoke perfect English.
Gigi, the female, was only 13 months old when she passed away, she had an incredible vocabulary for such a young bird. Had she lived longer, I reckon she would have given Mishka some stiff competition.
Mishka, my present bird, is capable of having a full conversation with a human, knowing and understanding what is being asked.
It all depends on the time and effort, that a guardian is willing to give the bird. Find a method that works for you both, having lots of fun, is the key to a happy talking bird.
Some birds may never talk, no matter how much training is given.