I used Omnifocus and it was/is great, I have gone off Iphone now and I miss it, I have a note 8 and a note 2 and I use Nozbe and it is the best by far and I have tried all of the GTD type task managers, the main things I like: you can email to it, so when an email comes in forward it to your nozbe account and it will pop up, you can setup a google calendar for nozbe so any dated/timed tasks will appear in there, you can also create an entry in the calendar and that will go back into nozbe. You can add comments, todo lists and take photos and upload files to a task, which works but is not 100% robust in my experience so you have to be careful. It has the ability to add projects and contexts and put tags on projects, so for me I have a tag called work and a tag called personal, and then I can attach those tags to projects to filter from later. It is way off omnifocus in terms of slickness and robustness and you have to pay 8eur / month to use it (if you want more than 4 projects) - but I think it is the best you will get for the android, you can also log into a webapp and add and manage tasks in there also.
I cant understand why people are trying to get some way of syncronising omnifocus and trying to get it to work on the android there is no need to get the syncing to work, the main plus point of omnifocus is that it looks beautiful and is very slick and functional. someone just needs to knuckle down and to a GTD app that is as good or better - the android apps are just to home-made looking (nozbe no exception) - the best looking app is Do it - this is beautiful and robust but is too thin in terms of power and flexibility.