XML sitemaps creation (mobile/images/videos/news/AMP/Hreflang) also for many 3PD extensions, top SEO features, htaccess + robots.txt editor.
Ease of use
Top, especially since data source plugins for many extensions are already provided. Wizard + SQL Query Compiler help to manage other cases.
The support is excellent. Quick and detailed answer guaranteed. John even developed a data source plugin for the 3PD extension Jomres.
Comprehensive manual as PDF for download provided. With this I could even manage myself to set up a data source for a 3PD extension.
Value for money
Top price / performance ratio. I don't regret having bought the JSitemap Professional Edition. On the contrary, it was a very good decision.