I can second that. https://www.mapbox.com is a particularly notable technology on top of OSM. Initially I wanted to use Google maps with some customs styles but found their styling options pretty limited. Even worse it's too unreliable in China and there's no way around it. I used mapbox to easily create a nice map that incorporated our branding and then http://leafletjs.com/ to add interactivity on top of it. Very happy with it.