What is the best cryptocurrency exchange at the moment ? well that all depends on whtat you consider the BEST ?
There are around 5 major playersin this market and there are many more popping up everyday. You can get exchange websites built for under $500 so almost anyone can do it, this also means anyone can scam you.
These are the most trusted crypto exchanges used today.
All of these services are based in the USA and are currently not regulated.