neither fingering is wrong but it all depends on the chord progression you play which fingering to choose, for instance if you would go from Em to G played with the 1st,2nd and 3rd finger then fingering Em with 1st and 2nd finger would be easier and quicker but if you're used to take the G chord with the 2nd, 3rd and pinky then 2nd and 3rd finger Em would be better,

Herman