Honestly, I would choose Alakazam over Malamar, because Alakazam has higher stats, and has less weaknesses. Well, kinda. And yes, it is speedy and a very powerful Special Attacker. Malamar is 4x weak against bug moves, and the fact that most bug types can out speed Malamar is horrifying. Here's a moveset for Alakazam
Alakazam @Life Orb
Ability-Magic Guard
EVS: 252 Sp. Att/252 Spe./4 Sp. Def
Timid Nature (-Attack, +Speed)
-Psychic
-Shadow Ball
-Calm Mind
-Energy Ball
NOTE: In-game Alakazam
(Not for competitive)
Hope this helped you made your decision :)