For me, I have 1 g12 character (I'm at 900k), so slicing to 6* doesn't make any sense for me right now. The 100k credits for winning the battles are better for me now than the slicing mats. Eventually, I'll need those mats but I'd prefer to get something I can use now.
Overall, I like GA and believe the match making RNG process is as far as possible. I'd love it if more people would actually play rather than just sign up and collect rewards for not participating, but that's their choice. I'm still having fun thinking about defense and offense squads. GA will definitely improve my TW teams as well. The event is longer than I'd prefer, but I don't know of a better way to do this than they are currently doing so that everybody around the world has enough time to place squads and attack (they've already tried events/windows with less than 24hrs and it cause too many problems for everybody).