As an end-user I like how games made with Twine with Sugarcube look and function, authors also have an ability to change the CSS as desired. The ability to hit the browser back button and go backwards a scene is nice 
I don’t have any non-adult examples to link to however. You can mostly find examples over at tfgamesite if you search for html engine however.
Also chyoa .com has some nice design (again also adult content)