We gathered our "best practices" but needed non-technical descriptions for the business user communicating their preferences to the creative design agency (if you really want the technical details take training and/or read this post by Frank M Taylor).
So let's look at some user stories for those using an in-context CMS editor:
"As a CMS user I need the ability to add content to and from the page. I should be able to add, re-order, or remove content in the in-context or form-based editing interfaces."
This translates into movable elements. Lists and “flat” markup are preferred where possible—especially on a page. This lets editors add, move, or remove in the Content Manager and Experience Manager.
You don't need markup to see which is easier to manage. Here's an example from our CMS Design Principles training: perhaps your presentation looked like a box of sorts:
A B C
D E F
G H I (that's the end of the training example, the rest is my metaphor)
Would you prefer a list that automatically displays in rows?