What are some alternatives?
When comparing XmlSitemapGenerator.org and Screaming Frog SEO Spider, you can also consider the following products
DYNO Mapper - Create Sitemaps with the DYNO Mapper Visual Sitemap Generator.
Pulno - SEO Audit and Website Analysis. Pull up your SEO.
XML-Sitemaps.com - Free Online Google Sitemap Generator.
Moz - Backed by industry-leading data and the largest community of SEOs on the planet, Moz builds tools that make inbound marketing easy.
MySitemapGenerator - Online XML Generator for SEO and eCommerce. Creates XML Sitemaps, Shopping Feeds, RSS.
Netpeak Spider - A desktop tool for fast and comprehensive technical audit of the entire website.