They're both really similar: both a dark blue-toned purple cremes, both two-coaters. So if you don't want to look too closely, you can declare them alike and just get one of them.
left: China Glaze, right: Kiko
However, if you pay attention, you'll be able to see some differences. The China Glaze polish is a little darker, and also seems to be more purple-toned. That makes the Kiko nail polish a tad lighter and more blue-toned.
Still, these differences only show up when you compare them directly, side to side. I personally prefer the Kiko one more, because it like the blue undertones and to me, its consistency is better. The China Glaze one is a little thick, the Kiko one not, it's way thinner. I wouldn't say you need to have both.
So what do you think? Close enough? Or are those utterly different to you?