I think the only real gotcha that catches me frequently is "className"... The rest, not so much. Also starting to like JSS as well. It's just such a natural fit, even if it feels much more verbose. JSX does feel much more like HTML + JS to me than any templating library ever has. From handlebars/mustache to angular, to vue, to whatever else. JSX is a realization I'd been hoping for since first working with E4X (which never gained adoption outside moz), it was just a nice way to work with things, and imho JSX is better still.