I have used the PineBook with Linux and with the Linux RISC OS port in the past. Two weeks ago I bought the RISC OS port. Very nice. Have to try a lot of software.
Any, like ArchiEmu (with a mirror of mei A5000 harddisc) and DOSBox-X (with a working Win98 installation) just for fun, other like rNTFS (an NTFS reader for RISC OS), Iris (with Thomas modifcation of EtherUSB to use an Huawei 4G/LTE surfstick) for real use.
Looks like the PineBook pro will be my "main portable Computer" in the future.
It is not too late, if you would like to send in a picture of your RISC OS screen (maybe even with some as yet unreleased software to tease us). Full details are here