IMHO the worst part of Edge is the UI and relative lack of configurability. I suppose you'd like it if you were already used to Chrome/ium, but I abhor the dumbed-down featureless "flat" trend that's infected everything "modern" these days, along with the lack of things like user stylesheets and zone-based security settings (both of which IE has had for a long time, and which I have used to much benefit.) I'd be far more welcoming of a new rendering engine in the normal IE UI, along with all the configurability it had.

(Disclaimer: long-time IE user --- as well as Firefox and (pre-webkit) Opera.)