Thanks! We do have in-task checklists, try editing the task description, you can add checklists to the task description using a Github-style markup. Also, Android and iOS apps are coming soon! :)
I feel a little dumb missing the checklist now - there's a big button right in front of me! Nice!
One last thing that would prevent me from switching: I don't see any terms of service or privacy policy on your site.