Here is a list of issues encountered when using this tool on many websites; not a big problem on small websites, but on bigger (300 pages) it's critical, and blocking on huge websites (>1000 pages)
Sitemap Order
The arbitrary order of the sitemap is not respected during the migration: recently modified pages appear first.
Aliases are lost and replaced by an empty page. The aliases have to be rebuilt.
Internal redirections to the site: hard redirects pointing to internal urls of the site (I know it's a bad idea to do that but some people do crazy things) are distorted during migration.
These are all very important issues to me as well. Sitemap order, aliases, and external links are hopefully low-hanging fruit and are important for simply getting a basic page structure set up.
Here is a list of issues encountered when using this tool on many websites; not a big problem on small websites, but on bigger (300 pages) it's critical, and blocking on huge websites (>1000 pages)
Sitemap Order
Block Expand collapse
Links no longer works after import.
Multilingual site
Page matches are lost during migration.
Layouts
Layouts are lost during migration. They must be redone by hand (the contents are preserved).
Galleries, Sliders & Videos
Galleries and sliders must be checked, as well as video insertions.
Permissions
Advanced permissions are not included in the new site
CSS on blocks
All manual CSS modifications made on blocs with the core included WYSIWYG tool are lost