GSC installed a 22KW Generac generator for us. I could not be more pleased with the company, both from a sales point and all through the installation. I had LOTS of questions and they were both patient and thorough with their answers. They showed up exactly when they said they would and the advice, installation and instructions on the generator's use was great.
I interviewed 4 Atlanta area companies and GSC was neither the lowest nor the highest. I selected them primarily because of their obvious professionalism, which was proved throughout the sales and installation process. They were very easy to deal with and, as stated, highly competent.
I would recommend GSC VERY highly, (something I rarely do,) for anyone even thinking about installing a generator.