I'm in for more new users. Experience is important, but since it's a really new service, and you had your success, it can't be that bad.

You can focus on making the experience better after getting some more users and more feedback.

If someone is going to leave because of the experience right now, well, there's always more people not using the software than people using it... Make it attractive to new people first, and then make it better for those using it.