Wow, that sure is an annoying product page. Where are the details about what mail providers they support? Does it do calendering? What are the system requirements (WinXP, OS X 10.5, CentOS 5, etc...)?
edit: ah I see https://news.ycombinator.com/item?id=5860776 , around a month then.
As a downside, I see that it doesn't support Exchange and that pretty much dooms it for me, at least on OS X. I hate Exchange, but I have to deal with it. Luckily, Apple's Mail.app seems to work fairly well with Exchange so at least I'm not forced to use Outlook.