If users other than the creator can experience it without being totally lost, it's time to launch. Aside from known security holes or absolute breakage, things can be iterated and added in as a work in progress.

For one, the features priority list may be different from the masses... creator may think that Feature A is what everyone wants, but in actuality users care more about Feature B. Or someone may suggest Feature X that was never considered, which makes A & B completely irrelevant.

For two, a good way to get an idea of where a UI/UX excels and fails is to hand it to people that are unfamiliar with it. The flow may make perfect sense to the creator, but the unseen problems will become apparent once others start using it and giving feedback.

Overall, if someone is wondering "is it time to launch?" then it's probably time to launch.

Thanks for your reply, you're totally right about the features priority, I think I'll have to just wait for a couple of weeks to make sure that at least there is no obvious bugs and security holes.

If by "wait" you mean work furiously, then yes by all means do that ;)

Hi

Many people will use the MVP idea as a guide - Will people find it useful if that something isn't refined or added?

As soon as there's someone that would be happy to use what you've got.

When your main feature works.