*Albireo could potentially provide low-level modem-like access to internet via SLIP which means having the IP stack on the CPC side instead of it being done by the peripheral like in the M4 board, and having a bridge server on the other side. But it would not be convenient. Also, just like the X-Mass, the Albireo does not provide RTC functionality.
*M4 Board is [https://unidos.cpcscene.net/doku.php?id=en%3Aannexes the fastest measured solution for mass-storage on the CPC]. It is a very complete and convenient solution with NTP-based RTC and Wifi network and very future-proof. But that means sacrificing historical pretense as the M4 board does all the hard work regarding the filesystem and network protocols for the CPC. As the Internet stack was never to be implemented on the CPC during its commercial lifetime anyway, does historical pretense matter for that kind of stuff?
*ULIfAC is the newest one. It seems quite similar in terms of functionality to the M4 Boardoverall, but not compatible. Don't know what it's bringing to the table that is not covered by the M4 Board.
Pushing to the limit this tough question: should we lock the CPC forever with its expansions from 1993? Or should we accept that the CPC can read mp3 files, run Far Cry and play 4K x265 videos on a modern graphics card and CPU expansion with a second monitor?