I have tried both to about lvl 20. They are both pretty nice, depends on your style (or what you like). Sword is nice for nuker because: shield increases block rate wich saved me a bunch of pots and even my life at some points. The knock-down and stab books are great for a nuker because it lets you escape if need be.
Spear is nice for int because: the passive increases your HP by a very helpful amount, and you get the stun move which is equivlent to the sword kd & stab.
So there isn't a better build, just go with what you like.

Good luck.
-Kayson
Edit: The best way for you to find out which one you like the most is to do what I did, try both of them and then decide. Go to lvl 16-20 or something.