Scenario: There is 300 users that buy our product on a Kickstarter campaign two months ago. We need to create these users account on our database and notify them.
We have thought two ways to accomplish this:
a) Send a email to each user with a link for creating a new password. It means that users will have an additional step to perform a login on our service.
b) Send a email with a auto generated random password to login and, if they want, change it on a future. Less steps but we see a problem here: auto generated password is not a friendly password (ie: lmd932ca) but our service remember the password forever so the users don't need to remember it.
Which is better? a) or b)? What do you think?
Edit: the core application, meaning where users sign-in/up is a mobile application