First impression: heavy and slow. I use search engine to search something, not to read news or watching pretty pictures. Why not just a search box, a button, and a logo? Sure, it's probably gonna be looks like Google, but hey, it loads faster.
Agreed on that. On first look, reminded me somewhat of Bing few years back. Eitherways, I presume it's search quality would probably be as good as DuckDuckGo[and worse than Google since it doesn't track] ; in which case, why choosing Quant over DDG is a better reason?
Totally agree on the heavyweight problem of the default version. But you can go to the lite version: https://lite.qwant.com/