It's clean, and it works... but I really don't see anything innovative or unique about it. The "large banner area with product image on one side and call to action button on the other" seems to be a pretty standard layout for web apps. Not necessarily saying it is a bad thing, but it does loose it's impact after a while.
It might be a good idea to use a slightly darker background color on the left nav column -- that'll help distinguish it better from the content, and reduce sheer amount of white on the page.
Looks sleek to me, especially because my browser window happened to be at the best width for the site. With a bigger browser window, it can seem a bit plain, but I still thought it looked good.
Also maybe its just me, but it seems like the content wrapper under the sliding article section is not centered perfectly. Looks like there is a gap on the right side.