User-submitted reviews of multiple aspects of a business?
In Drupal 7, you can create a review as a custom content type.  Staff could be rated as "very unhelpful" to "very helpful" using a field of type list (integer).  Quality of clothing could also be done with a list (integer).  For the time customers spent at the store, the field type to use depends on what you will do with the data later.

You could then create custom displays for this content type using Views.  Views integrates with Display Suite as well so you could use that if you liked, though I'm not sure it's the best solution.

As for the averages, you'll need to know some PHP, but you can use the Computed Field module.  Even if you are not very familiar with PHP, there are many examples on that module's documentation page.

If you're new to Drupal and all of this is very confusing, I highly recommend the book Using Drupal published by O'Reilly.  The second edition just came out recently and covers Drupal 7; it contains an explanation of how to use fields/content types and views (chapter two) as well as how to build a job posting site (chapter three) and product review site (chapter five), two examples that would probably be highly informative for you.

Good luck!