I like how simple this library was for me as i'm not very familiar or good at javascript, so all in one package everything you need! The only thing about retinajs which could be improved would probably have more support of other browsers (maybe even older versions) than just Chrome/Firefox etc., but maybe thats because im missing out something? It's great having such nice tools available when developing mobile apps especially if your targeting iOS users who generally use Safari browser instead chrome / firefoox ect..