Think about your actual morning. Do you wake up early enough to enjoy a slow brew? Do you have a kitchen at the office, or are you at a desk all day? Are you the kind of person who forgets lunch because the meeting ran long?

• Time: If you have 5 extra minutes, hot whisk. If not, iced.
• Gear: If you don't want to buy a whisk, iced.
• Taste: If you love that frothy, umami-rich cup, hot. If you want something icy and fast, iced.
• Workspace: If you have a kettle and sink nearby, hot. If you're at a desk, iced (just bring a shaker).

Most commuters I've talked to end up doing both: hot whisk on slow weekends, iced on rushed weekdays. That's valid too.