Spines is considered by far the best because of its range.
Yeah, same for stakers .. there is a problem: it suks 
Course as stalker u don't really need primary ( i mean, u have AS ..) but with spines u deal ridicolous damage, exept for as, and it suks.
It is range, well.. but when ur best spell (exept as) hit for 100 hp.. 200 when crits .. well it suks.
And about rage.. Mu works good, shark also...
So point is, i have a spines/regen stalker and i can't change it (too many ios) .. but i don't think i ll make another time the same mistake.
[censored] the rage, gimme damage!
If not spines, I'd probably make fire or broadsword.
Sword sounds good at all.
Looks like good and, if it is also great as damages and animations' time...
Well if it is... this is my choise.
(Question: why katana suks for any class?? )
As title says, i wanna make my first scrapper (my first hero really).
Point is, i'm quite sure about secondary : Regen. (I love regen, it works so good for stalker.. i think it must be nice for scrapper too).
But i haven't any idea about primary.
Can u help me?