Well, for my use cases no one has made a better device in the past 4 years so I'll keep using it as long as I can find fresh batteries to feed it.
The main demotivating factor is that Qt has such a large fs footprint that you pretty much have to clone the system to SD first before being able to do anything serious with it. The vm footprint isn't insignificant either since it has to coexist with the entire Hildon stack. Presumably, as such things tend to do, more recent versions would have grown a bit.