Perfect example why you can't look in the rear view mirror. SFO has experienced some rapid 737 growth due to recent bids. Without additional large bids in the future that extreme bubble won't exist.

Without doubt SFO and EWR are destined to continue in evolve as UA's international mega-hubs and there will be lots of movement in both.

Which one will result in becoming a line holder faster for a new hire is a crap shoot, IMHO.