I need some help

So I can't figure out which sounds better, granting the melody a little more spotlight or including choirs in the middle of the process?

This is an epic arrangement of Schala's theme from Chrono Trigger, for those who are interested.

Personally, I think it works a lot better if you have the choir on the sustained notes leading up to doubling the melody, like you did in the second version. It creates a nice feeling of suspense during the long tones, and satisfaction once the choir comes in with the melody. 

Additionally, if you could start at a slightly lower dynamic and build up to the moment where the choir joins the melody, I think it would create an even more satisfying and dramatic effect. However, I don't know from this clip how this section falls in the overall context of the piece, so you'll have to judge for yourself whether that would sound good in this particular section.

First of all, I really like it. Dramatic, powerful, but above all epic.
However, what I miss is a sort of resting point where the audience can recover their breath. Right now, we are submerged in drama and epicness, but there is no point of rest, except the final end. The need of a resting point depends on the context of the rest of the piece. When other parts are namely very restful, this piece does not need a resting point.

I echo fishyfry's points. The music itself is already epic and I do not think that you need to add (even) more lines to it, which can lead to an ocean of epicness. That can be pretty fatiguing. . . The key is to double parts, which increases the power, but the music still sounds dense and not over the top. 

Well done, I would say the second version.