I'd known of the G-Line series for a while, but wasn't very familiar with it. Over the past few years, I've had the opportunity to use it frequently in a certain online Gundam game, and it's become one of my favorite suits.
When the Standard Armor was made into a kit, it was pretty much decided that the other armor kits would also be made, so when the Light Armor was released, I of course bought it.
You can also build a version fully equipped with a backpack, but I think I prefer it without it because it gives a more Light Armor feel.
Now, I'm waiting for the Assault Armor, my personal favorite, next...

HG G-Line Light Armor | shin's Gunpla works