Re: The most trustworthy International Exchange ATM... (Or international retailers).
am pretty damn sure not all exchanges will be ready to Buy your bitcoins at current prices,and it did happen in the past when btc made it as high as 20k usd.
The price was above $ 7,000 for several months and no exchange platform complained about the price rally. It is a measure of how willing to pay for 1BTC. 
The best platform depends on your country and the documents that you can provide because exchange services need a trusted third party so this list will be different from one person to another because of the legal restrictions and the adoption of BTC against the local currency.
As for those who accept BTC for payments, most of the sites are either directly accepted or through intermediaries.