I finished off a can of GOEX 1Fg today, and then I tried some 1F skirmish powder.
I was firing blanks only.
I really couldn't tell the difference between them (other than a 2/1 difference in cost :-)
Fir what it is worth, I do believe that it is not 1F"g". The "g" means that it is "glazed". I don't think this is glazed. While that might matter for smaller granulation (to flow better), I havn't seen a difference in the big granulation.
There may be some difference in moisture resistance due to glazing. The metal can should keep moisture out anyway, so I am not sure if that would matter a whole lot. For the 2/1 price difference, I am pretty happy with it.
If shooting projectiles, I might stay with GOEX. I am assuming that you get more lot/lot consistancy for your money, and given the expense of the projectiles the cost difference may not be worth it for projectile shooting.
Even that theory could be proven wrong of course.