Hi, the difference is that with the Developer's version you also get all the theme's graphic files.Each theme is first designed in a graphics application and then converted to code (PSD to Html).If you buy the developer's version you can open the files in photoshop change the colors or position of elements (and a lot more) and then "export" it to your website.Generally you will have to have basic knowledge of photoshop and wordpress theming.
Let me know if you have more questions about the theme.
Thanks.
