I have tried several habit tracking tools. One of them was great in that it was easy to use across all platforms (Windows, Mac, iOS, Android, etc.), but when I snapped my streak, it was a terrible feeling.
That is where Polar Habits makes a positive contribution to habit tracking. I have found that I continue to persist towards my goals and habits, but if I miss a day, it doesn't blow up in my face and cause unnecessary regret. I pick right back up the next day and build the track forward.
I look forward to seeing this tool evolve (i.e. maybe a mobile app, even though creating a shortcut on the home screen works fine and I haven't had to log back in once I bookmarked or placed icon on my home screen!) and to supporting the team behind it. Great software all around.