Even though I’ve made it to Ruler status the past two Splatfests, I haven’t got to experience these yet. I purposely play during the last half of the fest too…so just my bad luck.
I find them to be intense and more chaotic. I haven't yet been the attacking colors, always been the leading/defending color. It's a lot to focus on. I've only managed to win one so far, lol.
I find them really fun and have gotten several. I’ve probably only won a match or two more than I’ve lost. I’ve also always been on one of the attacking teams.
As far as I’m aware if you are on the defending team getting them is completely random, but if you are an attacking team make sure you choose tri colour battle from the menu. It’s still random but I believe you won’t get them at all if you just choose regular open.