Just wanted to add my experiences with MtGox to the pile...
I sold $26,000 USD worth of coin on MtGox in mid June 2013 and made 3 withdrawals to my Thai bank account (10k, 10k and 6k respectively) between 15-19 June (my withdrawal limit is 10k USD).
Waited 10 business days before sending them the first support ticket, asking for a status update. Got the standard reply posted by others on this thread.
Each subsequent ticket I sent (about 1 per week) was immediately closed by their support staff without any explanation whatsoever.
Finally, on July 25th I sent them a ticket saying:
If I would cancel all my withdrawals, how long would it take to have my money available to purchase bitcoins again ?
Support staff replied within an hour:
Hello,
Thank you for waiting and sorry for delay. As per your request. We have canceled your withdrawal request and the funds has been credited back to your MT GOX account.
Due to a change in our banking system we are currently experiencing a back-log of withdrawals that we need to process.
Our team is working hard to increase transaction speeds, but there is approximately a two-week back-log we need to overcome.
It will take a few weeks to get back to normal, and we thank you for your patience during this time. We will keep you on update once delay has been fixed.
If you have any further enquiries, please do not hesitate to contact us.
Best regards,
Mt.Gox Team
Note that they immediately went ahead and cancelled my withdrawals, even though I never explicitly stated I wanted them cancelled.
Being very concerned at this point, I bought coin again and moved them to Bitstamp.
I went through their ID and address verification process within 24 hours, sold all my coin and made a withdrawal for the full amount.
On 1 Aug I got an email from Bitstamp staying that my transaction had been processed.
Somewhat surprisingly, the fee for this transaction of $25,600 USD was only $20.
Today, Aug 7 I received the full amount in my Thai bank account.
At least some exchanges seem to do what we all expect of them.
I can accept delays and issues, but being ignored for 7 weeks at MtGox is just unacceptable.
Cheers.