Sadly this is the best to do list I have seen.  Very glitchy.  Tasks done weeks ago magically show up and you have to delete them again.  A grocery list I didn't even want replicated itself 12 times.  My personal list replicated itself 13 times and when I deleted the second to last iteration of this it deleted everything I had ever typed into my lists.  Calendar support only available on ipad and android phone, not in browser window.  You have to trick the system into puting a date on items by setting a reminder and then going back in to deactivate the reminder.  I like that you can move items around however you want and that items left undone today stay in the today category instead of just floating out of the system.  It is odd that something as unfinished as this emerges as king of the hill in this category.  I would have thought that the global creativity and intelligence of humanity would have far surpassed this but apparently not.