I'm using it for several weeks now and I see how the application evolves. It started as a very well done piece of software and it's getting better with each release. I've never had any problems with. If you are looking for an application that will solve sudokus for you then Sudoku Companion is certainly a bad choice, but if you want to enjoy solving sudokus yourself then in my opinion Sudoku Companion is the best application for Mac out there.