I have a google chromecast (w GoogleTV) and the UI and lag is becoming a nuisance.
With Apple TV, do you get apps like Twitch and YouTube? Do livestreams work well? The most common apps I use are Twitch and YouTube but also Max, Netflix, Crunchyroll and Amazon Video.
I also had a Chromecast 4K and the Amazon Cube. For me, both are not at all comparable in terms of quality. One of the best features on the Apple TV is the remote control. Thanks to the touch surface, it is ideal for gaming.