The final push to start using Firefox over Chrome on Android might finally be thanks to the enormous selection of add-ons (Firefox’s version of extensions) coming out next month. Chrome doesn’t offer native support for extensions in its mobile app. Also, better security.
They do have a good overall ui, but the trust in them is less then it was before. Even if they did stop doing partnerships with Microsoft they also stopped keeping their users out of the filter bubble, meaning they filter search resualts out, while before they use to claim they didn’t do that.