Yesterday at Tijuana Flats in Daytona Beach I reached over the counter holding my S6Edge over the POS terminal swipe thing. I think the cashier thought I was trying to rob her, but when the POS terminal registered my card, she was amazed and brought her manager over.
A little riskier, but I handed the S6E to a cashier at a BBQ place, asked her to hold it against the card reader. She was amazed.
Only "impossible" location so far is the USPS. After finally getting their terminal to recognize my S6E, the terminal asked me for all my info (name, card number, etc). The transaction went thru. The employee was amazed, I was disappointed, but he suggested my card is now "in their system" come back to see if it is easier next time.
Final comment. After having resistance from Publix (grocery store in the SE USA) stores I tweeted their HQ, cc'd @SamsungPayUSA. Two weeks later Publix had trained their entire system to use SamsungPay.
Have fun with it.