Not trying to be nitty-picky here. You got a GREAT deal. And depending on what your needs are, you're probably fine. I'm just surrounded by pro designers everyday and have analyzed what they do ad nauseum.

The other problem is simply that a logo is but one piece of a big design solution for your entire company. You could, by yourself, fit the rest of your company's design assets around the logo. However, from my experience, without a great designer, you'll probably end up with something pretty spartan or messy. They know what to add and what to remove to the design in different realms (layout, color palette, interaction, etc) to make it have a professional look.