Agree fully with my friend Lerxst. I've flown both the Guppy and Fifi in SFO and the flying on Fifi is much better. Big however.... that can change on a dime around here.

Fifi is a much better place to spend time as well. More variety of destinations on the 737 and you'll be more senior, but my impression between the two is that quality of trips at 60% on the A320 list = 30% or so on the 737