I really like the website. There could be a bit more eye-catching elements on the front page, but besides that everything looks really clean.

But I have to agree - you should definately put up a section "What makes us different". When I was browsing around on your webpage all I thought was "What makes this different to Basecamp??"

So you don't necessarily make a comparison page, but highlight what you do better with your product than other project management software.