When comparing Casual vs Momentum, the Slant community recommends Momentum for most people. In the question“What are the best browser-based to-do list apps?” Momentum is ranked 14th while Casual is ranked 20th. The most important reason people chose Momentum is:
Momentum has a different, beautiful background image each day. It displays the time, a welcoming message and a reminder in the middle of the page and hides all other functionality out of focus.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Tracks task dependencies using a graph
Pro Great to-do templates
Every to-do list & project can be saved as an amazing template that you can re-use in the future.
Pro Offers a high-level overview of projects
The workflow with dependencies shows where the things are at a glance. No more frustrations of how your project is going and who is doing what.
Pro Sync deadlines to Google Calendar
To-do items can be integrated with your day-to-day schedule using Google Calendar.
Pro Visual way of organizing your work
The workflow includes dependencies and shows you where things are at a glance.
Pro Beautiful design
Momentum has a different, beautiful background image each day. It displays the time, a welcoming message and a reminder in the middle of the page and hides all other functionality out of focus.
Pro Provides with weather information
Current temperature and weather conditions are shown in the top-right corner.
Pro Built-in to-do list
Momentum has a simple to-do list that can be accessed from the bottom-right corner of the page.
Pro Reminds of the day's goal
Momentum asks the user what's the focus of the day and then shows that information is each time a new tab is opened.
Pro Inspirational quote
Momentum shows you a new inspirational quote, once a day.
Pro Displays bookmarks nicely
It shows your bookmarks and most frecent sites in a really nice way
Cons

Con Price
At its cheapest level, Casual is $9 per month for two users and two GB of storage. The trial period is short and there is no free version.
Con Some basic features not free
It costs to use features like changing the background manually.
Con Can't add bookmarks
You can't add bookmarks to it
Con Can't be customized
There are no customization options. Existing items can't be turned off.
Con 4K images not available
When accessed from a 4K display, the images will be bad quality.
