Crit strike for spells or more life? (Arc/Minion)

Hi There

I'm very near the crit strike chance for spells and it looks very tempting - I use Arc as main attack - is there any reason not to take these nodes?

Or do I need more defence - I have armour 815 health 1200 ES 125

Arc dmg per second 588

and I have a 5L zombie chest.

I can't decide whether to go for the crit chance with spells or more life and ES

I'm Lvl 47


Many thanks for any ideas!

Thx!