I ordered from MPC and it was a great experience. They threw in an extra sex-link for me (I had ordered one already). I did end up with a rooster, but it wasn't an extra - just a mistake in the sexing. It's a risk we all take, I suppose.
I will say, and I think everyone seems to agree - the customer service is fantastic. I was a bit anxious when I ordered my chicks, didn't want to wait too long, and they helped me figure out what I needed to change in my original order to get the chicks to me the fastest. They were extremely kind and helpful. They seem to really care as well - asked for pictures and a call when the chicks arrived. I actually just sent updated pictures of my girls to them here a couple months ago.
The warming pack is ridiculous and I ended up spending about $60 for 5 chicks (plus the one extra), but all my chicks arrived peeping and healthy. For someone who doesn't want 25+ chicks, I think MPC is an amazing alternative and I would highly recommend them! All my birds are gorgeous and healthy still.