Unfortunately I had I detour in social networks so the work on Todoist has been slow for some years. But about 8 months ago we started fulltime working on it and Wedoist. I think we have some amazing updates coming up that will solve all of your issues (ex. HTML5 enabled web and desktop applications and native mobile apps for iOS and Android).
Stay tuned and please provide feedback of how we can improve Todoist (here or on my email which is in my HN profile).