I just came back from lunch at a fast food restaurant where they were heavily promoting how you can over 100 flavors of soft drinks now. They had 2 brand new Freestyle dispenser machines. The part I found fascinating: despite a large, interactive touch screen display and a *fairly* siimple task, the restaurant had not one, but two, assistants helping each and every person get a drink.
When it wasn't quite so busy, I talked to each of the assistants and asked them how it was going, plus played with the interface a bit. They said it was going good. My take is that it suffers from a lack of visibility as to what optional flavors are available with each 'base' drink... some have 7, some have 5, some have none. They had tray sheets that showed all the possible combinations.
You might think that a 'smart' softdrink dispenser could be designed to be, truly, walk-up-and-use in this day and age, but that obviously wasn't the case, since they had staff helping people.
BTW, on an accessiblity note, there's a special button lower on the machine which enables some arrow buttons and has a dynamic labeled button (Enter/Pour) and transforms the upper display to work with a directional pad (Dpad). But, it was *really* difficult to get that accessibility button to work on the machine I used (hopefully, that's just a one-off problem).