Even at 1300 max mana spiritual attunement offers only 13 mana per second, id rather use other means to boost mana or survivability than that.
I can spam bears for a good 5 seconds before i have to run with 980 mana, and thats at 1.9 atks per second, which would spend approximately 250 mana per second.
My build requires me to move though.
with Big Bad Voodoo and Rain Dance rune, I can spam it almost indefinitely.
As I said in my previous post, it is not the mana regen which makes SA strong, it is the synergies with other skills
. I'll use your current build as an example.
At the moment you are running GI/GF/BR. If a monster dies and leaves a globe, you will get back about 120 mana (~100 from GF and 20 from GI). Since you are running with BR, you also get a 15% reduction to spell cost.
Now assume you are using GI/GF/SA. If a monster dies and leaves a globe, you will get back about 144 mana (~120 from GF and 24 from GI). You also
get an extra 12 mana regen per second. If you are killing things quickly, using GI/GF, and have a decent PUR I think SA is usually the better option.
There are plenty of other great synergies too, the best one being spirit walk (honored guest). With your current setup it would return 300 mana, but with SA you would get 400. Since you're already using GI, the cooldown on this skill should reset quite often, leaving you with massive mana regen capabilities.
I'm not saying SA is always better than BR for everyone, but it certainly works better for me...