Really? If you are serious about your startup, you should waste hours on a Coming Soon page instead of spending them on your product? Drop the few dollars on a service like this and get it other with.

This looks like a more ambitious version of something I worked on a little bit ago. Hopefully it works out for them. I think the key is to add features that developers normally wouldn't add if they made the page themselves (nice dashboard, populating a newsletter, sharing stuff, etc). It seems like that's exactly what LaunchRock is doing.