This app was mentioned in 2 comments, with an average of 1.50 upvotes
I like the andoku 3 and my favorite is sudoku4ever.free by onegravity. The 4 everfree I like the option to color the cells. Both of them has auto candidates and hints but 4ever has the option to choose which techniques you want to use in the hint system.
In short, the best i found so far (for android) is https://play.google.com/store/apps/details?id=com.onegravity.sudoku4ever.free
Got this one as FAOTD on Amazon (plus version). Best Sudoku app I've ever tried: Free version, Sudoku4ever