I've ordered from both. My chicks from MPC were all very healthy and most of them are wonderful. I got EE's who lay blue eggs and are friendly. My BO's are not huge, but large enough and one went broody this spring
I got 2 BR hens and 1 BR rooster and he was a mean thing. Had to get rid of him. But, he was pretty huge and beautiful, except he only had 1 waddle.
My order from Meyer was a big mistake. The birds are okay, my leghorns are a little small and my andalusians don't have much lacing, but they lay well. They didn't ship me one of the chicks I ordered, and then another one died within a week. They were kind on the phone about the one they didn't ship, though, and gave me a refund.
Do you have your breeds picked out yet?