...and I chose bitfinex because it doesn't have serious scam accusations...
There are many reasons why Bitfinex is a good exchange for trading, but this is not one of them. They have been dropped
by their banks, they are heavily involved in Tether (an entity that is viewed with much scepticism by many people in the
cryptocurrency world) and they got rid of their obligations to BFX token holders in a very opaque way. They didn´t outright
scam anyone as far as I know, but some things about Bitfinex are definitely suspicious.
On the other hand, they are the biggest exchange by volume and their trading engine works pretty well - even in times
of high volatility. This is obviously preferable to exchanges like Kraken that stop working as soon as trading volume picks
up due to high market activity.