There are several details that bother me about the site. First, the tabs don't have actual text, but use images with rendered text. The rendering in this text, and in many other places on the site, is harsh. I'm not sure what program you've used or what your antialias settings are, but the text looks "pixely" and dated.
In the main home page rotating banner, the "Learn More" button suffers from this poor text rendering too. Why not use an actual button with actual text? I know it's easier to just incorporate it into the image like you've done, but it seems unprofessional.
There are too many extraneous horizontal lines in the design. At the top, under the tabs, you use two lines to separate the headline (and "Prepare for Launch" text -- which, on a side note, is kind of cutesy but not functional and not terribly professional). On the Design page, you don't need 2 horizontal lines between each text section. The "tabs" used to label each section aren't very well defined. I'd say either make them more defined or drop the whole tab look.
The blocks of text are pretty tight for my taste. I'd increase the line-height quite a bit to let it breathe.
Other details seem dated or unfinished: the "reset" button on the contact form (who has ever used this button?), the difference in fonts / button style on the contact page between the "Send" button and the "Request a Quote" button, the way that "Need a Quote" is rendered text in an image, the blog only having one entry, the "Need a Quote" button in the footer doesn't do anything, the way that hovering over the tabs doesn't change their state at all. These details add up in a big way very quickly. Keep at it, do it right, and you'll give your visitors a much better experience and feeling of trust.