Mapbox GL JS is fully supported. Just log in, select any map and under "Use vector style" headline you can find source code examples for Mapbox GL JS, OpenLayers with vector tiles and Leaflet GL (plus OpenLayers, Leaflet and WebGL Earth for raster tiles).
For mobile development, Mapbox mobile SDKs, Carto mobile SDK and Tangram SDK (RIP) are supported.
On the desktop, you can use either QT or .NET with our maps.
A lot of people is choosing a map because of visual appearance. This is a great advantage of MapTiler, which has a tool where you can with a few mouse clicks totally change the map design, select one of 57 languages or a font for labels[0].
Advanced users can totally change the whole map by switching on/off map elements (schema based on OpenStreetMap tagging)[1] or add own data (MBTiles format - both raster/vector)[2].
There is a support for multiple JavaScript APIs like Leaflet, OpenLayers, Mapbox GL JS (source code snippets in the administration), mobile SDKs (Android as well as iOS) and desktop software development (QT + Unity game engine)[3].