I'm comparing Alakazam and Mr Mime. I think Alakazam is better.
Although Mr. Mime can use his Pokemon Power and reduce 30 damage and up,
Alakazam has a chance to confuse which can lead to damage, and Mr. Mime
only has 40 HP. Alakazam has 80 HP, because of that Mr. Mime can't do
that much damage. Alakazam has a 3 retreat cost agaist Mr. Mime's 1, but
i don't think that matters much, Alakazam would kill Mr. Mime before he
could do much damage to Alakazam. And Alakazam's Pokemon Power could
move a damage counter from himself to another benched Pokemon. And since
Mr.Mime has  weakness to Phychic, if the flip turns out to be tails it
does 40 damage and Mr Mime is dead.