Team Helix! I love Taron but there's still a very big gap.
In terms of setting, they're both pretty even to me. Taron is extremely well themed, Helix is not. But Helix has such a great location on the hillside in the city. In this case I take the "real" setting of Helix over the themed setting of Taron. Something about Helix just feels more epic and significant.
The coaster itself then. Taron's best bit (after the second launch, until the trimmed hill) is more intense than anything on Helix. However, the entire first half of Taron is just not that impressive to me, aside from that one twist after the tunnel. Helix's best moments deffo lasts longer and are more spread out over the ride. I also prefer Helix's last inversion over the trimmed airtime hill of Taron. It's no Blue Fire but still a really fun inversion.
I much prefer Helix's airtime over Taron's. Bigger hills with more sustained airtime. Taron has some short pops which are fab but not as impressive to me. The last airtime hill on Helix at night with the view is just amazing and not a single moment of Taron beats that for me.
Helix is far more varied, and has a more consistent flow to me. And a far superior layout. Taron has too many slow parts (and also some crazy fast parts), while I feel Helix flows extremely well and has a very majestic pace. It has a great mixture of all kind of forces. Less intense at parts perhaps, but I generally get a better feeling from it.
Taron has better launches. That's not even an argument. Taron gets all the points there. Taron is smoother as well. But overall I have a strong preference for Helix. Two excellent coasters though.