Pro AC: The service is generally better on AC in domestic J than on UA in domestic F. (However, it will not be the same as the International J you experience to TLV).

Try to pick 3000 series flights operated by 767-300. These will be the only flights that might have international J seating. (Then again, you might wind up with 'Purple Elvis' :shudder: )

Pro UA: You can probably change your tickets with MP, whereas once you ticket with MP on AC flights, there are no changes. If you don't think you will need flexibility, it's probably no biggie.