COINBASE is the way to go when purchasing bitcoins. Most trusted, been in the game for years now... I wouldn't reccomend buying elsewhere just because its so secure.
Coinbase is huge trustworthy exchange and it's high popular for Bitcoin and Ethereum buy/sell. But i'm disappointed because coinbase network supported more than 30 countries.
https://hitbtc.com/ is legitimate and top 10 exchange.
Coinbase is trusted in exchange so that being the highest recommendation among trusted sites,even many have used it from years to years.Their wallets are also very unique in that the efficiency of the user can easily do to other users provided by their features,hitbtc I don't doubt the market's greatness with more alt and tokens available there.