Feet DOWN for T/O, feet UP for LDG.
Airbus pedals are not like on e.g MD80, where you can stay on heels and just slide up easily when you need to brake. Almost impossible on Airbus.
Especially in x-wind ldgs, when you need rudder input and same time need/want to disengage Autobrake, you will be very happy having placed your feet on the upper stop of the pedals. The rubber cover prevent sliding up and you have to lift you feet to go on brakes, so reducing rudder input all that in x-wind. Doesnt feel good.
For T/O on heels prevents inadvertently disconnecting Autobrake in case of T/O abort above 72 kts. Below 72 not really a problem.
Dont know on Boeing a/c.