I use this site for Heisig, Anki for sentences and other things.
Reasons why I use this site for kanji:
1. It's very simple and focused. It was made to learn kanji and nothing else, which makes it very streamlined and well designed. Everything is made the way it is for the user to learn kanji by Heisigs method.
2. The shared stories, though I try to make my own as often as possible.
3. The failed pile. This makes a huge difference for me. Anki just makes you bruteforce the information when you fail, you simply have to redo it more times. The failed pile on this site is more of a dangerous location. When a kanji goes there, you get scared and you focus hard to make it stick so it won't go there again. If a kanji hits the failed pile more than twice for me, I usually rework the whole story. The failed pile lets me know which kanji I really need to focus on.
The only thing I wish I could do on the site, is change keyword. I use google chrome so I can not use greasemonkey to change it, but it really needs to be changed in some places. (Especially remorse and repent.. god I hate those).