I’m pretty sure mixer had a ton of features twitch didn’t have at one point but I could be wrong. I just remember watching kabby in the height of the pubg craze and he had a ton of cool stuff no one on twitch had.
They have some better and different features; but also lacking in some features people considered essential.
For me as a viewer, an easy example is that taking clips of streams is relatively new to Mixer, and you can't even sort/filter them. Clips helped build a lot of Twitch streamers' popularity by making things bite-sized and shareable.