2Do For TRO and GTD?
I've been using this tool for a few weeks and find it works really well for TRO. [Total, Relaxed Organization -Ed.] It supports multiple tags, smart lists, 2 dates, unprocessed task list (Inbox). It syncs to Toodledo and has iOS apps (probably Android too). Also supports AppleScript so I've got some fancy stuff that integrates it to Outlook and Evernote.
You might consider adding this to your comparison list.