Nirvana really excels in its simplicity. If you’ve used a GTD-style task manager before, getting your to-dos into Nirvana should feel very familiar. Everything is organised in the Project —> Task hierarchy with the usual Today and Next (as in sometime in the future) filters.
While not so much a feature, one great thing about Nirvana is the transparency in their development roadmap. Currently you can check out upcoming features. At the time of this post, an iPhone app is underway along with the ability to add recurring tasks, shared projects and a developer API.
If you want to give Nirvana a try, you can sign up for the beta for free using the invite code lifehack. Nirvana pledges to always have a free version, but after the beta period ends you’ll also have the option of upgrading to a paid premium account.
Nirvana (Sign up with code lifehack.)