here's a completely unscientific answer based on just watching people here, though it'd be interesting to have hard data out of a doc's office. if you allow for half a year to a year for full adjustment and results, i'd guess maybe 65% completely satisfied (that's about 2/3s), 20% somewhat or mostly satisfied, 10% marginally satisfied or on the fence, and 5% dissatisfied. which considering medicine overall might not be bad.