*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. Seems quite like an M4 Board, but not compatible. But it emulates the floppy-drive at a lower level than the M4 so that it has better compatibility. On the other hand , the M4 handles CPR files while the ULIfAC does not.
The problem is that these multiple solutions are incompatible and are fragmenting the CPC community. That means we have less compatible CPC software, and we get needless complexity and confusion for users and developers. Currently, the choice is as follows: