These have to be the bargain of the year, full ETTL triggers for a fraction of the price that the competition charge. So simple to use and reliable. They even look smart.
Two points to watch out for though are: 1. For ETTL to work you need to use compatible flashguns otherwise they only work in manual mode in which case you could have bought the cheaper Yongnuo triggers.
2. It is easy to accidentally change one of the settings by touching the buttons at the side. Changing the channel will stop the flashguns from syncing because it is vital that they are all on the same one. Change the group and you will get unpredictable results in manual mode.