I don't own one myself, but I've talked with numerous people who do and the only real negative feedback I get is that the bowl is made from plastic. As such, over time it can get scratched and even "cloudy" looking. I would recommend that when you clean the bowl you do it by hand, avoid harsh detergents, and use a soft scrubber.
The other issue is that they only hold about 5 liters, so if you are serving 6-8 oz portions you're only going to get 20-25 servings before the unit is empty. Depending on the foot traffic in your shop you might go through that pretty quick. And that, as you might imagine, can create operational difficulties on a busy day. As long as you keep issues like this in mind, the feedback I have gotten is that they work as advertised.
