Should we introduce subfolders into the URLs on a new site?

[oneresult]

A site we are working on currently gives no indication of the subfolders in the URL. Eg. the site uses:

www.examplesite.com/brand-name

Rather than:

www.examplesite.com/popular-products/brand-name

There are breadcrumbs on site to show the user what part of the site they are in and how they navigated there.

We are building a new site and have to decide what route to take:

Since the site is already performing relatively well in the SERPs and the URLs are nice and short this way, is it a good idea to keep them like this or is it better for usability to include the subfolders?

This post suggests that we would be best off to keep the URLs as they are - particularly since less would be changed http://www.seomoz.org/blog/should-i-change-my-urls-for-seo

Thanks in advance for your opinions!

Liz

@lizstraws

[oneresult]

(PS. we are obviously going to thoroughly 301 the old to new URLs so we don't lose any linkjuice.)