I’m a big fan of using multiple campaigns in PPC advertising for several reasons.
First, you can budget brands or products separately by putting them into separate campaigns. If you throw all of your brands or products into one big campaign, there is the possibility that one particular brand or product might overpower the others and never give the other brands or products the opportunity to play in the marketplace. If you budget the brands separately in their own campaigns, you are giving each brand its own unique opportunity to succeed in the PPC marketplace. Then, as more and more data comes in, you are able to scale your budgets up and down accordingly, giving more spend to the brands or products that are doing better and pulling back from the ones that might not be doing as well.
Second, you can more efficiently gauge the popularity of specific brands or products by isolating them in their own campaigns. A glance at their daily clicks/impressions/cost/conversions can convey a lot of important information quickly without you having to dig through one massive campaign and tabulating your brand data separately in a spreadsheet.
And I just like the organizational structure of it to maximize my PPC Advertising efforts here at JumpFly.