Bitfinex is really a good exchange I've been using it for the past 6 months without any major problem at all, it has really low fees (even though it depends on the trading volume), lots of altcoins, 2FA authentication, mobile app, support is really good but could be a bit better (they only support e-mail). Not being able to use in US is bad because even though I live in the Canada I'm always travelling between Canada and the US. Another thing is that verification for me took 7 days but for a frSee full review