To-Do List Dilemma

Clear_for_ios7_medium

via www.realmacsoftware.com

Google-keep-logo_medium

via www.viwoinc.com

I've been trying to find the one to-do list app that works seamlessly across all of my devices (iOS, Android, and Windows/Chrome). Clear is the best I've found for my needs (mostly homework) on iOS and Google Keep is the best I've found on Android and Chrome, but the problem is they don't play nicely together. If anyone knows of a miracle way to sync tasks between them that would be amazing and solve all my problems, by the way.

So far I've found Todoist and Wunderlist to be my only options in terms of working well on my iPad, Nexus 4, and PC. Todoist I haven't used much (waiting for it to be updated for iOS 7), but it's designed decently and meets all my needs. Wunderlist would be great (although the design is a bit "meh"), but I've run into multiple syncing issues with it so far.

My question is: for those of you cross-platform to-doers, which app/service has served you best? Again, if there's a way to sync tasks between Clear and Google Keep (I wish Google would just make a darn iOS app, already), I'm all ears.