I don't know those other OSs being a n900-lover.

One additional point: it is quite slow at bringing up stock apps like phone or messaging from the left-hand taskbar. About 2/3 secs, even if repeated (again, this is said of other devices, so why on this powerful device?). Thus key function apps are not cached in memory. This time to open is slow IMO, so I guess the expectation is that you keep them open and scroll to the needed functional screen from the right swipe.

Also, out of the box, you do not have access to the standard ubuntu repos. That has to be enabled (making device r/w, developer mode etc). As yet, I have no idea if "desktop" apps would run or how they would be handled by Unity8 in phone mode.