Should I get the app to a state where I can launch without any paid plans (just a single free plan) and just launch? Or should I stick to my guns, and wait until I have the paid plans sorted?
This worked pretty well for me; I can't say if it will work for anyone else, of course.
Are you writing all your own payment code? If so, why? I would recommend using something like Spreedly or Chargify (we use spreedly with TweetSaver). Getting payment integrated using Spreedly went very quickly for us. You should be able to get it up and running within a day or two.
I always vote in favor of launch early and iterate... but with tools like spreedly it's only an extra couple days at most to get payment plans in there.
I'm probably going to go down the Spreedly route. While I agree that it probably won't take me long to integrate, I need to make sure everything is solid. Also, I'm currently working a 9-5 job as well as working on my startup, so it might take a while.
* They will uncover bugs that have been missed
* They will show you where usability is poor in your app
* You will build an audience of people that actually use your app, giving you an crowd to sell to
* You'll get the opportunity to see how the app performs under working conditions
If you wait until your app has the paid stuff in, then the first paying customers may have to put up with problems that could have been ironed out during the free-only period.