Todoist seems to have decided to invade the planet, and their new apps are even more elegant than before (although, alas, their iOS app STILL doesn't include folding of e.g. subprojects and subtasks - most irritating!). Their Windows desktop app, on the other hand, is a model of streamlined elegance, with folding etc. They have probably the broadest cross-platform offering of any task management/outliner application (including Wunderlist). More info at todoist.com/next

Having said that, most of the really neat features (notes, tags etc.) are only available to users of the Premium version. Not expensive, mind you (USD 29 p.a.), but slightly irritating.

Cheers,
Bill