This article describes the current limitations of the solution.

Limitations

Hierarchical hierarchy vs flat hierarchy

Google site has a hierarchical organization of pages.
Each page can contain subpages and is organized in a tree.
For example: http://www.mysite.com/mainpage/subpage.
SharePoint stores pages in a flat library.
To avoid page name conflicts, Cloudiway renames the pages in the following way:
mainpage-subpage

Menus

In Google Site, the depth of menus is unlimited.
In SharePoint, the depth of menus is limited to two.
Nodes in a menu with a depth hierarchy greater than two are not migrated.
As a solution, you might envisage manually removing the default SharePoint Quick Launch menu and replace it by a web part text editor.
In this web part, you can build your menu.

The Google Site menu control can contain text. The SharePoint menu cannot. Therefore, text content in the Google Site menu control is lost.

Logo

Site logos are not migrated.
Programmatically, this would require modification of the master page of the SharePoint site.

Gadgets and web parts

Google gadgets that do not have web part equivalents are not migrated.

Google Form

Google Forms are not migrated to SharePoint.

Page footers

Page footers are not migrated to SharePoint.

Page templates

Page templates are used for creating new pages in your Google site. They have predefined elements such as as texts, images, gadgets, and more.

Page templates and their content are not migrated.

Side bar: Site Owners bar

SharePoint menu can contain only links to other pages or resources. Site owners bar is not migrated to SharePoint.
After migration you can add a ‘Site Users’ app from Web Part Gallery to display the list of owners in the page.