For me it's not a 1st, 2nd, 3rd priority, but some mix of factors. These for sure include price, # of stops, time of flights, duration if there is a stop.

I am willing to trade off one factor for another. What gets traded changes year by year, date by date. I'll definitely pay a premium for a direct flight. Luckily out of Toronto there are plenty on non-stops, but on several occasions we have had to make connections.

This year's trip we had to compromise on price because of the timing of University Reading Week. There were simply no cheap seats available. Thank heaven for points.