i often read post concerning the bad rewards from GAC, saying it's not even worth the bother.
I tend to disagree; if you win all your rounds and end at the bottom of the Kyber pool (Edit: in Div 1), here are your rewards from your monthly GAC (if I'm not mistaken, which is always a possibility):
500 crystals (promotions up to Kyber)
15 Holo mk3 (promotions up to Kyber)
30 Stun guns (promotions up to Kyber)
25 cuffs (promotions up to Kyber)
700 GET1(promotions up to Kyber)
10 zeta (promotions+GA winner x4)
15 omega (promotions+GA winner x4)
900 mod salvage (GA winner x4)
100 gold mod salvage (GA winner x4)
13000 GAC token, which could buy 185 kyrotech (3200 bottom of Kyro, 350x12 round winner, 1400x4 GA winner)
It's not arena level and most of us will get less, but still worth trying to get it imo.
Edit: breakdown of "where do they come from ?" added