Regarding volume, I tried to register for Bitstamp a few months ago, and it asked me for a scan of my passport and social security card.
That's not just a no, it's a "Fuck No".
That with the rumored difficulty of withdrawing, Bitstamp's KYC procedure has effectively killed off its volume.
Say wha?
Where are you from? When I made my account, my ID card and a phone bill was enough.
EDIT: And I don't see any difficulties in withdrawal, be it fiat or BTC.