It's mind-blowingly good. Easily on par with Autopilot (That is, Autopilot's ACTUAL capabilities, not what they show in marketing promos). For long highway trips, it's easy to go hours without a disengagement.
The full setup costs about $800, is completely plug-and-play, and you can order everything you need on the site (EON/Panda/Giraffe). See: https://www.youtube.com/watch?v=UfF9l2-orTk
There's a huge active community working on adding support for more cars and even custom forks with more advanced features like dynamic follow. Someone even recently got a VW bus working with it. https://discordapp.com/invite/avCJxEX
Also it's just really freaking cool to have a self driving Corolla. Can't stress how much this thing has changed the way I view driving and going places. It's no longer a pain, but a joy to sit in stop and go traffic. It's not perfect, but it's pushing the border of level 3 autonomy and far better than anything that any manufacturer besides Tesla is shipping.