I know it's not what you're asking, but the best weapon depends on the situation. Therefore, regardless of perks, a specific weapon or weapon type is often the most appropriate for a given situation. That said, I voted for the Fang of Ir Yut since, being a scout rifle, it's usable in the widest range of circumstances and has perk options which are also useful in any of them.

I don't have the Word, but have the others. Overall I like Fang the best. I use the others if there's a burn and small arms on. They're still fun to use.