While I have long been familiar with Sudoku puzzles, this is my first experience doing them at a rate of more than one per several years. I cannot imagine a more helpful UI that wouldn't feel like plain cheating. Which is to say that the UI is very helpful but I am still convinced that I am really good at solving. Doing puzzles on paper would surely be a slow and frustrating experience for me.
The achievements are well done, pretty standard for a Microsoft Casual Gaming game. I am working on doing all of the challenges for this month, but doubt that I will do them for 12 months to get all the achievements.