Hey crossword-loving people, I use Daniel Jalkut's fantastic Black Ink app to do crosswords every single day on my Mac. If you're more an iOS person then take a look at the new Black Ink for iOS:

Like its Mac counterpart, core features are free to use, forever … downloading puzzles from a variety of bundled “sources”, and solving the puzzles in the beautifully-rendered Black Ink grid.

Premium features including Check Answer, Reveal Answer, and planned future features such as printing.