It depends on your specific need, if you want something that is daily driver ready I recommend the OnePlus One, if you want something to hack on, and you're into alternative mobile OS, then consider to buy the PinePhone.
There's a signal text messaging application, there're a few 2 factor authentication applications, I don't know what anki is.
Hallium is an hardware enablement abstraction layer. We use it to port Ubuntu Touch and other OS, to devices that where built to run android.
We are not working towards android app emulation, we are working for running apps natively. We're doing this by using anbox, which basically is an minimal android image, with just enough to run apps, and that image is running inside an lxc container. However that is very hard to put it to work fully (access to sensors is one of the problems), and we have been asking for help with that.
Actually it's only Ubuntu Touch. The by UBports is used only to call attention to the broader community that does more than just Ubuntu Touch, we also have other projects around it that where craeted to serve our user and developer community.
Yes, I've been using Ubuntu Touch since 2015, as my only mobile OS on multiple devices, I'm also involved with the UBports Community, that maintains and develops the OS. I like it and it fits my needs, however it might not be for everybody, as there are way fewer apps, including some that many people expect to have.
However if you want to have an alternative OS, not based on Android, that is GNU/Linux with the necessary arquictecture changes to be reliable on a daily driver mobile devices, and that respects your privacy, then I believe it's the best choice.