What are some alternatives?
When comparing Time&Time and Timezone.io, you can also consider the following products
Spacetime - Work hour and time zone management for distributed teams.
Every Time Zone - Online tool for keeping up with times around the world.
Timezoner - Time zone calculator bot for Slack
Channel Time - Automatic time zone conversions for your team
FlagTimes - The macOS app for anyone working in multiple timezones.
World Time Buddy - Effortless time conversion and world time.