When comparing S7en vs Calendar, the Slant community recommends S7en for most people. In the question“What are the best custom Android Wear watch faces?” S7en is ranked 4th while Calendar is ranked 20th. The most important reason people chose S7en is:
S7en is available in purple, green, black, white, and blue.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Has 5 color variations to choose from
S7en is available in purple, green, black, white, and blue.

Pro Customizable
Editable with every image editor.
Pro GNOME native integration
Pro Currently in active development
GNOME Calendar is improved with every release cycle of GNOME.
Pro Simplicity
Calendar for GNOME aims to find the perfect balance between features and usability.
Pro Synchronisation
It has online accounts integration.
Cons
Con Some setup is requried
Requires installing Wear Faces app, extracting the zip archive in smartphone's pictures folder and selecting the pictures in the app.
Con Cannot print
Con Extremely buggy
Con Poor interoperability with online calendars
Does not connect to Fastmail.
Con Far too simple
Con FAR too tied into the GNOME infrastructure
The UI and configuration presume you are running GNOME, and has the ugliness of a GNOME application. Configuration, as is usual for any GNOME application, is pretty much nonesistent.
Con Can't read 'all-day' events with dark theme
Text is white on light blue with dark themes. The workaround: assign all-day events to just one hour.
Con Can't import ics files
Con Continues to pop-up reminders that are turned off and they cannot ever be removed
The GNOME Calendar displays pop-ups from an old Google Calendar that was used. That Google Calendar has long since been removed from GNOME, and even with the notifications turned off on the GNOME Calendar, the pop-ups still happen.
Con Incorrect appointment times when importing .ics calendars
Con No support yet for WebCal
No support yet for WebCal, such as those offered by Facebook events.
A workaround exists. Since this application uses the same background services as Evolution, installing it and adding the WebCal calendars there, also adds them to GNOME Calendar.
Con Only works on GNOME
