I just called Mariott support and confirmed what I already have read: They will NOT match Diamond status with HHonors to ANY Mariott status, even after mentioning to them I spend 200+ days in a hotel each year. They wouldn't even let me do the challenge to gold or whatever unless I had at least 10 days with Mariott. Too bad, because I would have spent my >$60k in hotel bills at Mariott in 2019 to mix things up a bit. Staying with HHonors for this reason.
Platinum Premier Elite with Ambassador
on October 18, 2018