Help! Should I build my +spd -def Soren or a +spd -def Nino?

Giving an objective advice is pretty difficult here. I like soren more, because he doesn't rely on gronnblade to be good and his personal tome makes him much more interesting than nino. Nino's upside is that she's strong even with the cheapest build, whereas Soren requires more attention regarding his skills.

EZ Nino- she's way better than him in most cases, even with Soren fully built, not to mention she comes with Gronnblade+, Draw Back, Hone Attack 3 and only needs Fury and Desperation 3, along with a +Atk or +Spd seal to be complete, while Soren needs a lot more expensive skill inheritance to be used to his full potential