It meets my needs.

Pros
[1] Simple UI
[2] Support Widget
[3] Use iCloud Sync
[4] The only countdown app I know that has both version of MacOS and iOS

Cons
[1] Texts in Widget are not fit to its Widget box
[2] Do not Sync until the app opens

Hope soon updates of fixing the Cons

Student :) about Countdowns - with Widget, v1.2.2