Hi all,

I have an award on CX from ORD in May. I can fly to ORD on either AA or UA. They pretty much arrive at the same time with about 150 minutes connection. The AA flight is a regional flight by Envoy while the UA flight is a mainline. The question is which flight should I buy? AA is $50 more. Will UA has better on time arrival considering it is a mainline flight? By choosing AA, I will at least in theory has irrop protection given this is all Oneworld flights but I fear regional flight suffer more delay and cancellation.
Any ORD expert opinion?