For me, archive.today, archive.is, archive.md, archive.ph, etc. are _not reliable_ for a number of reasons

But some archive.today users who comment on HN cannot seem to accept that archive.today may not work for everybody else

NB. Archive.today is not a "substitute for archive.org". Archive.today does not do www crawls

As for archive.org, I know of a number of alternatives but each is generally less reliable and/or less comprehensive than archive.org

Comman Crawl, i.e., downloads from data.commoncrawl.org, is reasonably reliable but not as comprehensive as archive.org. CC is not a reasonable substitute for archive.org's CDX service. The CC CDX endpoint, index.commoncrawl.org, historically has been easily overwhelmed and unreliable

As for archive.today alternatives (no crawls, only user-submitted URLs), ghostarchive.org seems well-designed but not used much. No CAPTCHA, HTTPS and Javascript are optional and HAR files are provided. Whether it gets blocked like archive.today sites I do not know

NB. Archive.today users may be using archive.today not as an archive but as a lazy man's solution for "paywalls" (Javascript annoyances)

Where that's the case, comparsions to archive.org or other archives that are derived from crawls are inappropriate