What are some alternatives?
When comparing phpSitemapNG and Really Good UX, you can also consider the following products
DYNO Mapper - Create Sitemaps with the DYNO Mapper Visual Sitemap Generator.
FlowMapp - UX planning tool for creating a visual sitemap
XML-Sitemaps.com - Free Online Google Sitemap Generator.
VisualSitemaps - Autogenerate visual sitemaps in seconds.
WonderWebWare Sitemap Generator - Sitemap Generator is freeware program that will help you to automatically generate site maps for google, bing and yahoo in their respective file formats.
UX Archive Animated - iOS apps animated user flows