During my travels, sure I could sketch in a sketchpad, but I didn't want to be completely cut off from painting digitally. So on investing in a Kindle Fire my thought process was that I could kill several birds with one stone -
1) having something to read on,
2) having something that essentially could act as a personal computer,
3) something to Paint and Draw on!
I used an app called 'Autodesk SketchBook', it's free and it's pretty good but you pay a small fee to unlock more advanced features (to replicate a normal digital painting program much better).
However, painting on Kindle is a bit like smudging paint around a canvas with your bare fingers (even when using a stylus). It's Jittery, unresponsive and generally very frustrating to work with. You'll find yourself constantly drawing and erasing areas you didn't intend the paint to cover. You can create nice artwork, but it's a bit like two steps forward one step back the entire time, because the stylus just never is precise and accurate enough.
Nevertheless, I've soldiered on with a few pieces and did come out with some nice artwork, but I feel that drawing these on my normal Macbook with Graphics Tablet would have taken a lot less time (maybe four times quicker).
So my conclusion? Definitely don't rely on digitally painting on your Kindle, it just isn't developed enough to work properly for that. I have heard that this isn't the case with painting digitally on Ipads, so maybe it's worth trying, though I have no experience of that myself so couldn't say for sure.
Overall? 4/10 - I'll be sticking to my beloved Macbook and Intuos Tablet for now :)
All the best,