When comparing 2Do vs GTDNext, the Slant community recommends GTDNext for most people. In the question“What are the best cross-platform task apps?” GTDNext is ranked 13th while 2Do is ranked 21st. The most important reason people chose GTDNext is:
All the “Get Things Done” lists you would expect: next actions, someday, waiting, and scheduled.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Flexible
2Do conforms to your workflow instead of forcing you to conforming into some preset workflow. It helps to accommodate your workflow through a series of features including tags, batch editing, configurable presets, and the ability to quickly add tasks at any time.
Pro Offers detailed options
Adding a task can be as simple or complicated as you like. A to-do list entry can simply consist of its title, or you can also add notes, recurrence, set a due date, tag a location, schedule an alarm, priority (low, medium, high, starred) and tack on a URL or photo. You can even make an audio recording with voice notes. And each list is sortable by a number of criteria, including priority and due date.
Pro Updates have remained free since beginning of time
Unlike many other apps that will release a new paid version when major features get launched, 2Do doesn't resort to that.
Pro Variety of organization methods
Use a combination of tasks, projects and checklists.
Pro Get Things Done-style inbox
You can use 2Do according to the Get Things Done methodology – or not.
Pro Advanced search
Find old tasks or organize smart lists based on complex search terms (for example, “tasks to do at home between 6 pm and 11 pm”).
Pro Support for Apple Watch
Pro Optionally sync with iCal or Outlook
The app can optionally sync with iCal or Outlook with free helper software available from the 2Do Website.

Pro GTD style lists
All the “Get Things Done” lists you would expect: next actions, someday, waiting, and scheduled.

Pro Automatic next actions
When it comes to choosing your next action, most to-do apps suffer from the same problem: All of your actions (sometimes hundreds in total) are visible to choose from. This can overwhelm users and cause them to give up on the system. GTDNext is different. In the "Next Action" view, only the very next action is shown for each of your projects. This results in a nicely consolidated view of only the things that need your immediate attention.

Pro Unlimited levels of projects and actions
In GTDNext you can set up an unlimited number of levels for your projects and actions, allowing you to plan your project and sub-projects in as much detail as needed.

Pro Areas of Focus
GTDNext supports the “Areas of Focus” methodology from Getting Things Done. You can filter all of your tasks to just show your work tasks, side project tasks, or personal tasks. There is also a global filter, so that when you’re hard at work you can focus only on your work projects and tasks.
Pro Option to visualize all projects and tasks in a single outline view
This is really useful because it prevents you from having to navigate through each project individually.

Pro Many keyboard shortcuts available
The number of keyboard shortcuts makes it easy to log or add tasks without removing your hands from the keys.
Cons
Con There is no way to print tasks or lists
Con Decreased cross-platform support, new versions only for iOS
For those that use multiple mobile platforms, support for the Android version has been dropped meaning there is no longer parity between the apps on iOS and Android.
Con No attachment capability
2Do will create a link to a file, but will not store the actual file as an attachment.
Con No mobile app available
Con Web only
GTDNext does not have native apps for other devices, but it does work across PC/Mac/Linux on the web client.
Con No Google Tasks integration
