Any thoughts on Battle Rouse?

Near the hp wheel, next to Vaal Pact.

It says "3% of damage taken gained as mana when hit".

Has anyone grabbed this node? Sounds good for keeping Arctic Armour active and not worrying that much about mana regen.

PoE wisdom, come to me.

It also makes MoM a bit more mana-efficient. Nice to have, but not mandatory.

I think it only really makes sense with mind over matter. If it's just for sustain, you can't really rely on it to help your mana elsewhere and so you must build as though you didn't have it. But if you build as though you didn't have it then there's not really much point in having it in the first place!