I have ordered birds from MPC multiple times. Every time, I have had them sexed (I want females), and almost every time I have gotten at least one rooster. The first order, I got four roosters out of ten birds. I lost two chicks, both appeared to be possible failure to thrive cases. Both died after their 48 hour arrive alive guarantee, and MPC was NO help when I was trying to save them, and didn't even bother responding to my emails about the birds for several days.
The second order, I got four birds, all four happy, healthy, and FEMALE. The third, four birds, lost two chicks, but MPC was wonderful and refunded my losses. In my current batch, I have a total of 14 birds, 5 of which I currently suspect could be roosters at 4-5 weeks of age, but every one of them arrived healthy and happy.
Over all, I am pretty happy with MPC. The birds are prettier than I expected, and their customer service is pretty good. It seems like the bigger your order, the greater chances of a small number of your sexed pullets turning out to be roosters. I spend the extra $ on sexing and vaccinating. Better safe than sorry.