When comparing OmniFocus 2 vs Notion, the Slant community recommends Notion for most people. In the question“What are the best cross-platform task apps?” Notion is ranked 10th while OmniFocus 2 is ranked 36th. The most important reason people chose Notion is:
Even the right-click menus on the web are the same as the app.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Organize tasks into projects
OmniFocus 2 allows you to organize tasks into Projects, allowing you to keep your tasks organized in the best way to stay efficient for that project. Each task also features summary dots. For example, red means the task is overdue and orange means its due soon. There is also a range of other dots that can be specific to projects.
Pro Forecast summary
The Forecast Summary shows a quick glance of the tasks you have that day. You can tap on any day to quickly see what tasks you have planned that day. For extra functionality you can connect the iPhones Calender app, which allows you to also see any other events you have planned that day.
Pro Excellent full stack support from phone, to tablet, to Mac
With very good synchronisation.
Pro See an overall view of tasks via "Perspective"
The Perspective section allows you to see an overall view of the tasks you have set. It also allows you to set contexts or see things you have flagged.
Pro Superbly customisable via Perspectives
Pro Picks up reminders added via Siri
Pro Best support for GTD in the marketplace
This really supports the implementation of David Allen's Getting Things Done
Pro Nearby and context-sensitive tasks
OmniFocus 2 allows you to set up contexts for tasks in certain areas. This makes sure you never miss a task when you're out running errands or happen to be near something you need to do. Just set contexts around places you frequent or set as a specific task.
Pro Client side encryption
Pro Apple Watch integration
You can send lists from your iPhone, and get notifications on your watch each morning with any tasks you have set for that day.
Pro Full-featured on desktop, mobile and web
Even the right-click menus on the web are the same as the app.
Pro Unlike anything else
One of the most complete applications one can use to build a personal dashboard (or professional) and migrate all other services to it. No more calendar, task, notes, financials, lists, writing and wiki apps, just Notion.
Pro Pages within pages within pages, to infinity
You can have a ridiculous amount of information within a single note. Look at how it works, you'll be surprised!
Pro Flexible contents storage and organization
You can upload files and embed online stuff in any hierarchical structure using pages, toggle lists, etc.
Pro Highly visual, with icons next to every new page and so on
This feature makes it very easy to find certain notes and such. And great for visual people as well. You could also add images as icons instead, if you like.
Pro Blocks offer incredible flexibility
The basic unit of organization in Notion is the block, which can be a chunk of text, an image, a bullet point, or even a link to another page. Each page consists of these blocks, which can be easily reorganized, moved to other pages, converted into other content types, or generally manipulated in many useful ways. Because of blocks, restructuring information in Notion is way easier than in any other wiki or notebook app.
Pro Does a great job with both notes and to-dos
To-dos in Notion aren't just dot point lists. You can drag and drop them into columns just like Trello (Kanban style), you can have sub-tasks, and you can easily mark things off as completed so they are no longer in your way. Notes are also powerful, with proper formatting and ways to manage and search for them, which makes it a great Evernote alternative.
Pro Cross platform
Works with Android, iOS, Windows, & Mac OSX.
Pro Awesome for wikis
You can easily start writing a bunch of web pages, share it with co-workers and choose whether to publicize or keep your contents private. It's also easy to hyperlink pages.
Pro Amazing view flexibility
You can create different views for a page's content and easily toggle between kanban, table, etc. (As long as the content is able to allow different views.)
Pro Quick and effective search
Just type in a word and you'll have results in no time at all.
Pro Attach files in tables
You can attach files in table cells, which is a feature missing in most spreadsheet-like applications.
Pro Great spreadsheet functionality
You can use calculation/formula, links, attachment, inter-referencing of data from other pages or tables, embed documents and images in the table cells.
Pro Renders Markdown Syntax
Add code blocks, Headers, bullet point, numbered lists, or To-Do boxes by typing using Markdown Syntax (instead of klunkily moving the mouse to formatting boxes)
Pro Less headaches when editing pages
Lets you restore your page to a past edit. Also works with sub-pages and databases. Though it is worth mentioning that it's a paid feature.
Cons
Con Very expensive
$40 for a to-do-list app is a bit much, even with all the other features it offers.
Con Limited to Apple devices
Must be used as a native Mac, iPhone, iPad, or Apple Watch app. There's no cross-compatibility with Windows, Android, or web.
Con Only one context (tag or label)
This won't stay a con for long. With the pending version (Omnifocus 3) to be launched in 2018, Contexts are being replaced by Tags. Yes, finally...you can have as many contexts as you like for a particular action.
Con Slow sync in Europe
Con Not very fast using native apps
Can take time if you're switching between lots of pages often as it needs to load the data each time
Con Not always very intuitive
Column filters are not that intuitive to apply.

Con No true backup
True backup can only exist if it's automated and easily recoverable. Else, it's just an outdated copy or useless scrambled data.
Con Designed with teams in mind, and less formatting than Evernote
Evernote may be more individual-oriented and has more formatting and such options available, but whether that affects you is down to personal preference. Try both and see which you prefer.

Con Not yet a new protocol, as it could be! (or could it?)
Think of scuttlebutt or email. the best Evernote alternative would be a "web 3.0" of sorts. Something that would be just a simple file added to a computer and automatically replicated to other computers along with a website and any company could easily pick up the concept and make their own hosting, including some awesome google drive/host of sorts.
