Hi Bill,
Which menu system to use with the template set most likely depends on how many pages you plan on having on your website. If you have 10 or less pages, then the menubar.php will create a linear list of the links for navigation.
If you have more than 10 pages, then a linear list may be more difficult for your viewers to navigate, and the flyout menu makes it easy to group related pages and quickly navigate your site. It also has the side benefit of creating a single-page sitemap showing all the pages on your site.
The flyout-menu is a bit tricky to configure as the flyout-menu.xml requires perfect XML syntax (or else the whole menu system doesn't work), but it's easy to add items/test (using flyout-menu-test.xml and ?menu=test on the URL) in a parallel environment, then when the menu looks fine, copy flyout-menu-test.xml over flyout-menu.xml and upload flyout-menu.xml to implement your changes.
Hope this helps...
Best regards,
Ken