Why is AirDrop so slow?
It could be interfering with existing wifi network, you can use the Airport command line tool to disconnect from other networks:
Begin by linking it to a another location:
ln -s \
/System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport \
/usr/local/bin/airport
Then, disconnect from the current network:
sudo airport -z
You should be running at about 10 Mbps !