Yeah we use one. I have been trailing it for 5 months now on certain rounds, and slowly people are starting to come round to it, and have said what a great idea as we keep hearing cheques are going to be phased out. If the customer is in i get them to pay this way instead of cash or cheque. It is great for the one offs like gutters and conservatories, and also for the outstanding debts as you can call up and collect the debt over the phone. This was the big plus for us, as we were/are always owed big amounts each month, so this has cut that down! I am also surprised at how many people pay via credit card and pay the surcharge. Also its less paperwork and running to the bank.
All in all its working, so thinking in the new year to get another couple.