I love it and would hate to go back. You have a normal sized phone that can make various otherwise awkward activities on small factor quite comfortable unfolded: note taking, film watching, reading, Internet in general.
It is so good to be able to whip this out anytime, anywhere.
It literally replaced 3 other devices for me that I used to drag around to cafes, work and when travelling.
I considered this overpriced bs until I got to try my friends device. Now I just consider it overpriced.
Hinge durability is the main concern.
I would not buy in yet unless you plan to upgrade every ~2 years.
Make sure the manufacturers warranty is solid.
Software-wise, I've not had any issues whatsoever.