Not the best, not the worst
It's picross, so it's fun, but this version has a few problems:
1) It is hard to switch between "fills" and "x"s.
2) When you finish all the numbers in a column, they don't grey out.
3) The cells are just a little too small for my finger, and there doesn't seem to be any way to zoom in.
On the other hand, there are features about this one that I like:
1) It shows a window in the top that has a previw of what you have finished so far.
2) You can't delete an x while you're in fill mode.
3) You don't have to fill in straight lines.
Final verdict: Not a lot of puzzles (only 70), no zoom, unprofessional look and feel, but with some features you don't see much. Is that worth the investment? in my opinion, only if you've beaten every other picross game on the market.