We have developed CoScreen with a highly customized screen sharing encoding and distribution pipeline which offers high performance, low system consumption, and low remote control latency.
The quality you experience highly depends on the quality of your network connection (more on this here: How can I optimize my network quality to have a better CoScreen experience?), your overall system consumption, and sometimes issues related to your specific OS version or hardware
If the quality indicator in CoScreen indicates that your app performance is not optimal, open your local performance monitoring tool (e.g. Activity Monitor on macOS), sort the applications & processes descending by CPU consumption and close any application that uses a considerable amount of CPU.
Also, sharing windows can take up to 60% of one CPU core on older systems because CoScreen captures them at a higher quality than most other tools.
We have also had reports of high CPU usage from some users on macOS Mojave. Upgrading to a later release of macOS is thus highly recommended.
Finally, certain external monitor configurations, and particularly display adapters, can cause issues. Pleasure let us know if you come across and particular device that doesn't work well with CoScreen.
And you can always open a ticket or drop a note at firstname.lastname@example.org to report a problem.