Neither of them need any attack. Even though Espeon's defense is better, Alakazam is a better sweeper: has more speed. You probably haven't done the EV training for them.
Alakazam can learn the elemental punches. It has a better movepool. Just because Espeon has a bit better defenses and sp.attack, Alakazam will get almost unbeatable after 2 Calm Minds.
Alakazam@Salac berry
Psychic
Calm Mind
Thunderpunch
Fire Punch/Ice Punch
Espeon@Lefties
Psychic
Calm Mind
Baton Pass
Substitute
See the diffence? Espeon can't do anything against dark types like tyranitar and houndoom, while Alakazam can do a good damage to almost everything.
I prefer to use rather Alakazam because of that. Espeon doesn't counter Alakazam well.