The iOS app is a great complement to the web version, but it’s also functional enough to effectively replace it, depending on your workflow and needs. The ability to turn MindMeister mind maps (also on iOS) into agile projects has been especially appealing to me.
There’s Apple Watch support built in to the iOS version, too. Of course. I don’t have an Apple Watch yet, so I can’t tell you much other than that I’m a bit jealous of all of you who have taken the plunge. I do know that it allows you to create, assign, and complete tasks right from your wrist, and has support for predefined messages and voice input for efficient responses. Dick Tracy will be more productive than ever.