A personal story about Bitfinex: A couple of months ago my cellhpone was stolen from me, containing my 2FA. Given the high ammount of funds i had on the account at the time, it was possible (But unlikely) that they would be at risk. However, after a couple of hours, Support confirmed that there had been no activity/login attempts on my account, and after a quick ID validation, reset my 2FA and allowed me to set it up on a new phone. This marked me, as the speed and efficiency at which the support verified everything to make sure my funds were safe and remained safe was unlike any other exchange i've seen. Will continue trading and recommending Bitfinex!