Do you know what the basis of that opinion was? As an outsider, how do I know that 1Password is managing its own security better than LastPass has?
They do what any reasonable security company does, and call in vendors who have negative incentive to lie: https://support.1password.com/security-assessments/
I was especially impressed by the Cure53 ones, where they were provided access to the source code: https://bucket.agilebits.com/security/Cure53-1PW18-report.pd...
See page 10 [1] which explains how the secret key provides extra entropy (which makes it much harder to brute force a user who choses a weak password). Also see Story 1 on page 11 [1].
[1] https://1passwordstatic.com/files/security/1password-white-p...