Hi
I am going to begin weekly travel to Montreal,QC from LGA-NYC for around 1 year.

I am free to choose a carrier. There are flights between Montreal and LGA by United, AA, AC. I do not have status with any of these but have 60K miles with united and 25K miles with AA an 0 miles with AC. I am confused which carrier should be my choice/preference.

Air Canada miles might not be very useful as I can't use them to anywhere but canada. Can I transfer them to United??

My important concerns are:
1. Ability to collect miles which I can use for flights between US and Asia. I feel sticking with Star Alliance is good options.
2. On time and ease of checkin at airports.

Please recommend me based on your thoughts.