So that means 5+4.75(9.75)% mana is worth more than 3.09+3.19(6.28)% reduction, but 9.75+4.55(14.3)% mana is worth less than 6.28+3.30(9.58)% reduction.
9.75% mana > 6.28% reduc.
14.3% mana < 9.58% reduc.
I guess it's an INCREDIBLY small difference then, in the end. As the difference between the two mana returns is ~46%, and the difference between the two reduc values is 52.5% in the end, while for 2/3 (in both) it's 48.7% for the mana, 50.7%.
In the end, I guess that means that if you are doing Progress and can expect to fuck up (read: Die), Moonglow will be better, and if you're farming easy content (easy being whatever you can rely on not fucking up on) you'd take Furor, as the furor talent will only yield it's full benefit assuming you have a full manabar and you get to use all the mana, while moonglow works no matter what?