Have you ever used one? What were the fees and the experience like, and would you use one again? Is there one nearby where you live?
I have not used one and I heard that the price is a lot higher than regular exchanges and sometimes than Localbitcoins.
I believe the BTM business model is not that feasible and a better way to go about it is to keep all transactions online by having a website/exchange that accepts debit cards and OTC deposits.
Maintenance costs will be lower and you will have minimal hardware upkeep which can be an inconvenience.