I like it so far, and today I saw the option of :Unlimited: relay / email accounts as a paid subscription from FF. Nearly 1 US dollar a month, so not too bad a price point.
Screenshot from order form:

Given that there are many other fine options- Cloudflare, Duckduckgo, and even apple (paid) - would you consider the FF Relay? What merits/ demerits do you see?

• Multiple domain support
• Multiple email accounts
• Storage quotas
• Vacation response
• Easy managment (I will only setup the VPS and another person will add the mail accounts as they are needed)
• Admin GUI
• Ability to rate limit (per domain and email account)
• SMTP, IMAP, POP3
• Webmail

I have considered the following options:

• Mail in a box
  

• Mail Cow

• VestaCP / HestiaCP
• DirectAdmin (Free License provided by the provider)
• Redmail (is discarded as it requires a subscription for some functions that are needed)

Which one would you suggest as a better alternative from the ones I mentioned or do you kown a better option?