Definitely recommended!
Booking process is relatively easy, book and paid online (we used WeChat), then, as explained, you get ticket confirmation 15 days before the trip. We booked business class tickets which are obviously popular so there is no guarantee you’ll get it - twice we received an email marked ‘urgent, 15 days before, that they had to put us on the different train same day, which was ok for us but keep in mind if on tight schedule. Boarding is 10-15 min before the train, suggesting being at the station 45-60 mins earlier (in big cities) especially if it’s your first train. Stations are great, well organized, look like airports. Your passport is your ticket, just scan it at the check in. Finally, Chinese bullet trains are fantastic, clean, punctual, and business class is fabulous, worth every penny!