the best thing to do is pick 5 or 10 states you are most likely to go practice in, call the state boards themselves, and they'll tell you. there is a link for the state medical boards' phone numbers all listed here on valuemd.com
i've already talked to many of the state boards, and they look good, except of course CA.... NM & KA are trouble... TX may be trouble in the future. PA? most the states out in the west look good, which is where i'll be practicing one day (OR, WA, UT, CO).