Sailfish isn't open enough for me, they have closed source UI components and I couldn't even find the build recipes for the packages they provide when I tried.
They do not support full disk encryption, although it has been asked for by the community for ages.
Also Sailfish tries to abstract components from Android with libhybris. I wanted to have a real Linux distribution, which does not need some sort of Android compatibility layer to actually work, or else it would just run behind Android and the phone industry (as I've worded it in the introduction post of pmOS).
MeeGo has its last release from 2012 (according to Wikipedia), so one would need to update everything first, deal with the legacy stuff that it brings and fully maintain it from there. By using an alive desktop/server Linux distribution all the regular distro maintenance does not need to be done, it just needs to be bent to run on phones.
Finally there is the pmbootstrap component. I've started scripting everything before I developed it and realized, that I need a real program that abstracts all the bootstrapping and cross-compiling. The result is, that you can install it on any Linux distribution, that runs Python 3.4 and OpenSSL, and it sets up all the crosss-compilers and else everything you need in chroots. I haven't seen any other of the existing projects doing something like that.
(We also have the deviceinfo files, and the one-package-per-device thing, which I haven't seen anywhere else.)
I'm not Ollie but I'd say the main strengths of pmOS is that it's lightweight (Alpine is a small Linux distro) and that it seems to aim to be structurally simple (only one package changing per device supported). There's probably some additional strengths in having pmOS as a community-led project, with no need to navigate the bureaucracy surrounding earlier attempts.
Would be interesting to know what can be shared from those projects. For instance Jolla are just preparing to release Sailfish on the Xperia X, I wonder how much assistance that will provide to this project as well. Sony have an Xperia Open Devices programme which at least puts some effort into running on a mainline kernel.
We have used the usb network configuration code from SailfishOS' hybris-boot as reference to implement our own version for the initramfs already.
What these projects can share is mainlining kernels at least, and there could be more. We have heavily documented what we do and I hope that this will prove to be useful to other projects as well.
Meego or Sailfish are niche systems compared to Alpine and it's my understanding they don't graphical applications from desktop Linux systems, though I'd take any GNU over Android.
The problem is phones require a different UX than desktops. That’s the reason why Apple has two similar but different frameworks between iOS and macOS, and windows 10 attempts at cross-device (touch or mouse, your choice!) have largely failed. A menu bar, for example, won’t work well at all on a phone but is ubiquitous for X-based apps.
I'm honestly not convinced of this. I know it's gone terribly so far, but it's not clear to me that that's an interface issue and not an ecosystem problem with the phones in question. A menu bar, for instance, would certainly be unwieldy, but themed with large text it's no different than toolbars which certainly are found on mobile. It would frequently be clunky, but even limited support for the universe of existing software would in my opinion have a massive effect on the usability of any new platform.
