campbx seems the most viable of what you've listed, but has high fees.
coinbase is not an exchange, I use it all the time...but not for trading.
coinmkt is in beta, doesn't seem to have any volume and doesn't have an API, so doesn't seem viable for trading yet.
bitfinex is still in beta-test according to their website, so doesn't seem ready for volume or trading either.
None of these would seem to be viable high volume exchange replacements for Gox or Bitstamp. Not that I can get my bitcoin out right now anyway because they both fail so hard...but once I can I'd like to know where to go.