Pro’s and Con’s of having Register/login vs. only login

What do you guys think is better for the user experience:

Having single sign in:

New User/Returning User --> Sign in Modal --> social button --> Authentication --> User Home

New User/Returning User --> Sign in Modal --> E-mail --> Authentication--> /Outside Platform clicks link in E-mail/ --> User Home

  1. Users just need an email/social to start using the service regardless of their account status.
  2. Back-end is on charge of the differentiation returning users vs. new users.
  3. Sign in will be passwordless
  4. E-mail sign in will prompt a secure link sent to user's e-mail.

Having a Registration/Login

New User --> Registration Modal --> Authentication --> User Home Returning user --> Sign in Modal --> Authentication --> User Home

  1. Different flows for different users types
  2. New users will need an e-mail/social link to create their account
  3. New users will need to fill basic registration form for identify user type.
  4. Returning users will need an e-mail/social link and a password for using their account.

We're having having this debate in my company right now we have the first flow with only one way of signing in same for new/returning users. We've been experiencing some complains about some will mistype their email AND create a new account and not understand why they were not seeing their information in their User home.

I lean towards having registration/sign in differentiation

  • Keep Web standards.
  • Not rely on user's memory for login into the right account
  • Create account give us the opportunity of creating a more complete user profile
  • Consistency will rely on the design
  • Get rid of additional step of clicking on your e-mail to login.

Right now we don't have many returning users and we're focusing on getting sign ins but in the future we would need to have a better flow for returning users to avoid friction.