The above linked survey is from May of 2012. It shows 83 percent of survey respondents thinking about quitting due to Obamacare. It also shows the highest ever numbers of docs opting out of Medicare and Medicaid.
Most significantly, 61 percent of docs are already finding it harder to adhere to the Hippocratic ethic of medicine. (Bear in mind that some specialties would not run into as much conflict with this due to the nature of their practice.)
Results are from a faxed survey of random doctors with a total of 699 respondents.