I love the design. It's clean, simple, and NOT all web 2.0 with clouds in the background. It's a bit text-heavy, but honestly I think this is fine. Most of the time when I see a site for a product, I want to read about what it does, not sift through a bunch of pages with huge images at the top.

So good job on the design. I also don't notice any glaring grammatical errors (native English speaker).

One tip I have: the screenshots on the right hand side of "Features" look a bit like they are part of the page, but then they are also cut off so it's a bit visually confusing. I'd either put them all in a row somewhere so it's more obvious they are just images OR fade them out a bit (lower opacity) so it's more obvious they're graphics and not actual page elements.

Overall I love it!