Even if you've registered your relationship with your partner, you still have to provide evidence to prove the relationship, in 4 aspects - Finance, Nature of household, social, commitment... best if you guys have some of the evidence already...
By simply looking at the numbers, partner stream seems to have more quotas than Employer, however, I think there're A LOT of people on that stream too....
https://immi.homeaffairs.gov.au/what-we-do/migration-program-planning-levels