I have switched to using absolute positioning via CSS classes for most of my page layouts.
I have a problem when working with various control wizards, more likely an issue with VS 2012, but I think other Telerik customers may have the same problem and hopefully know the solution. See attachment for an example of the HTML Designer window.
In the example, the menu appears at the top, as expected. The grid jammed-up against it, and attempting to select the Item Editor just selects the master page zone.
Previously with flow layout, the controls were spaced so that access to the item editor / wizard buttons were easy to locate and click.