My little business has benefitted (to a degree) in 2013 by the use of a 3G debit card machine, with a contactless option.
However, it's efficiency leaves much to be desired, and fails to complete the transaction on about 50% of occasions. Luckily, the customer will usually be patient and try again.
The contactless option frightens many customers, has no PIN number to aid security, and has only ever been used once in my shop. Also, the customer does not receive a receipt when using that option.
I found that strange, so I queried it with Barclaycard, the provider, and they confirmed it was something they were 'looking at fixing in the future'