Im a few slots away from maxing it out. I like having the projectile and have a relic that gets me bonus souls when absolving. 

Cross attack spamming is necessary at higher difficulties. 
 
With that said, I've got both trees maxed out, and I'm three achievements away from trading the game in towards Bioshock 2.  I just need to find the rest of the holy and unholy relics, as well as get all the Virgil commentaries (apparently, I missed two of them somewhere around the first three circles of Hell).

I maxed out my holy track first.

I maxed my holy track.
The cross is a really effective weapon. By the end of the game all I had to do was spam cross attacks and maybe use some magic.

I'm two slots away from maxing it out, I don't think I put anything into unholy.

I maxed it out as my first track also. I figured it would come in handy more than unholy.

I did so on my second run, damn that cross is powerful!