Currently, there are about 8 hours left until the next guild battle begins. By winning the previous guild battle, I was able to increase my Merits balance to 6000, which in turn means that I could buy exactly 3 Gladius Case in the guild store.
I just did this and got some good cards. Among them was a Legendary card and a Common Gold Foil card.
At the moment I don't play the new cards very often... probably because I have to get used to the new abilities and the new rules for guild battles. But slowly my Gladius Collection is getting bigger and bigger so that I can soon play quite well with it and choose from a wide collection of different cards.