This has been a great app after quitting. There are some good looking apps out there that help you quit, and this one helps you stay off. (I didnt use one, myself, but when I found this I found another app that would have been great! I couldnt do patches of vaping, so I opted to cut back progressively for a few months before quitting on my 30th birthday, and I saw an app designed for that.) This app, however, was absolutely worth the purchase. I bought it with the weight tracker.
To the dev: Id recommend more stuff. Maybe articles/links to articles? I go to this app whenever I get a craving, but more information would always help pass the craving time.