I had some small problems flashing the UBPorts image, but not the same or as bad as for n900user259. I couldn't get the device automatically recognised, so selected manually. Then the process appeared to have hung, but on reboot the bootloader was a UBPorts branded one (very pretty by the way). On second attempt things were smoother, still manually selected model, and it booted correctly.

I'm not a huge fan of UT (I have the original MX4 device with the latest image installed) but I thought it was worth trying out. I found a few issues, but nothing dealbreaking (couldn't get gps lock, no keyboard illumination, no ringing from the device when bluetooth headset connected (possibly, not confirmed, I saw it once at setup, but didn't go back to check later)

I had a lot of problems flashing back to Sailfish. After reflash the device was stuck in a bootloop at the startup screen. Tried following Kabouiks TWRP guide, but I couldn't get that to work - complaints about not finding /vendor when installing from the zip file (tried via SD card and internal storage).

Eventually flashed back to the original image, also via Kabouiks guide, then immediately installed the lastest SFOS image once I confirmed booting into Android (ugh!).

All seems well now, back on SFOS, and it seems to have cured the bluetooth issue I had after flashing to 3.4 a few days ago.