If indeed you do get a choice or at least wish to make your choice known, they I would highly recommend Boeing. Schedules changes, routes change and well, everything seems to change and in my opinion there is no way to accurately predict it.
But one thing hasn't changed for sure and that is that 777's are easier to fly, easier to deal with SOP's and in general are better aircraft, but that is just my opinion. In addition, there is far less 'talking' required on the flightdeck to get safely from A to B, in a Boeing than on an Airbus. I won't even get into the relative simplicity of Boeing procedures as compared to Airbus.
Just take a look at Airbus FCOM's, OEB amendments and FCI's and that will give you a good indication of how needlessly confusing some things can be on an Airbus.