I'm gonna go with MCC. Not necessarily because it's mess was worse, but because it's the franchise with the strongest and most venerable legacy, and Halo IS Xbox. As a celebration of the whole history of Halo all stops should have been pulled out to make sure the collection launched without a hitch.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix