When comparing Things 2 vs Emacs Org-mode, the Slant community recommends Emacs Org-mode for most people. In the question“What is the best cross-platform to-do list app?” Emacs Org-mode is ranked 5th while Things 2 is ranked 17th. The most important reason people chose Emacs Org-mode is:
Users are not tied to one service provider, program, platform, or database engine.
Specs
Question Ranking
Pros
Pro Daily review
At the beginning of every day, a yellow box appears at the top of the Today section, displaying all tasks scheduled for this day. You can investigate them, and then decide which ones you’ll have for that day and which one you’d rather want to delay.
Pro Cloud sync
Users need to create an account for Things Cloud (the account can be created from any device). Once signed up, cloud sync will be active, and you’ll have to login on all of your devices to complete setup. From that point on, syncing happens in the background. It is invisible and always reliable.
Pro Easy to set up and use
Things 2 works from the moment you start it up. Simply add a task and when you want it done by. You can also add notes to tasks or tag when you need them. Things allows you to quickly and easily start keeping track of your tasks.
Pro Project support
Things 2 has a projects feature that allows you to organize your tasks together. You can select a project you need to get done and Things helps you focus on each task to get it done. You can even group projects together to focus on the most important aspect of your life at the time.
Pro Nested tags
It's very easy filtering tasks that belong to various areas (etc private vs work)
Pro Great for GTD
Things is one of the best apps of doing Getting Things Done.
Pro Customized calendar
The calendar view (when selecting a due date for a task) is a customized, scrollable version of the default iOS calendar view. This makes it look familiar, but also functional for Things 2's requirements.
Pro Files are usable anywhere at anytime
Users are not tied to one service provider, program, platform, or database engine.
Pro Ultimate flexibility
This app's flexibility is based on its minimalist approach, giving the user near-infinite freedom.
Pro Agenda views
Pro There are a lot of extensions, for exporting to html, bootstrap, js-reveal and much more.
Pro Absolutely free
Emacs with Org-mode is free as in beer and free as in speech – that is, it costs nothing and it’s totally open source.
Pro Incredibly extensible
There are many plug-ins for Org-mode, including Org-habits and Org-notify. If Org-mode lacks some piece of functionality, it is very easy to add it.
Pro Supports plaintext spreadsheets
Pro Efficient features for deadline organization
Pro Quickly add rich text
Pro Excellent unofficial Android app (orgzly)
Cons
Con Expensive if you buy apps for Mac, iPhone and iPad (all sold separately)
As at May 2016 if buying all three apps it cost $80! That said there is no annual subscription and I've been using Things for years and have only paid once so far.
Con No supported time based/location based alarms
Other apps have these abilities, and they are very useful. Especially for a $10 app, it would be great to include these premium features.
Con Android app isn't very good
There are several user-created apps for Android, but none seem to offer the same level of functionality as other to-do apps.
Con By default, a hard-to-read display
The default way of writing an outline or checklist creates a very messy wall of text that's difficult to read with no vertical spacing. You can manually add vertical spacing, but the Org operations don't preserve it. There are pretty-display modes, but you need to remember how to enable them, etc. etc.
Con Unintuitive user interface
The key combinations are unintuitive and difficult to remember. This is probably because there are a lot of hidden "modes" depending on where the cursor is. Actions aren't paired with reversing actions like in other todo apps. For example, hitting shift-tab does NOT reverse the effect of hitting tab.