I think it looks great, just a few thoughts (mostly on UX/UI):
1. You probably can do without the <hr> tag separating the head and the rest of the body on the landing page
2. I see a signup button, but not a login/signin for existing user
3. I find the font a bit quirky, but that's just my preference. I try to do non-cursive font for easier reading
4. The about page: a) url is sprint.im/user/about--that's a bit weird as I'd assume it's just sprint.im/about b) shorter paragraphs and make the long paragraphs about "why Sprint.im different" into a list
5. Quick tour page: the bounding box of each step needs some top/bottom padding/margin. They're connected to each other right now.
6. Register page: a) help text for password is "secret salt" I get it, but I think the word salt would be confusing b) I don't like the arrow icon to the left--it's too big and too gaudy as a list icon
7. Just another thought/question for discussion as I am also wondering about this myself. It's a B2B/Saas, I wonder if the fact that it was made by one person should be pin-pointed (on the about page). Most people would prefer that their software is made by a team/group/company. Having a single name as designer/developer takes away that illusion of "faith" and can turn a lot of people away.
I think it's a great project. Congratulations on launching your beta. It's a great step and you should be happy and proud of it. Now just iterate like a machine and I'm sure you'll definitely see some interesting movement. Your space is interesting in that: there's a lot of players, but there isn't a king or someone who basically rule the rest (well, basecamp/jira maybe?), but that means if you focus (which I see that you are) you'll capture some market share that other guys haven't or can't seem to do. Good luck and as always, please update us on each iteration.
-V.
