I travel a lot on business and have been using this tool for a while.
The main consumer problem it solves for me is the "I'm in Barcelona on Tuesday and need a conference call between Atlanta and Ukraine. What is a time that's workable for everyone"
It's indispensable for that problem for me. Filtering TZ and adding TZ would be a nice additional feature though.
Have a look at http://worldtimebuddy.com/ - i am using it for exactly your use-case. It is really convenient to only display some specific time zones and search for a specific timezone, country or city.
The main consumer problem it solves for me is the "I'm in Barcelona on Tuesday and need a conference call between Atlanta and Ukraine. What is a time that's workable for everyone"
It's indispensable for that problem for me. Filtering TZ and adding TZ would be a nice additional feature though.