I have no idea on the taste. The last spring bear I killed was in an area where he had probably been feeding on winterkill, although I don't know for sure. The meat was awful, and I don't know whether it was from 1) diet, 2) age (older boar), 3) spring bear fresh out of hibernation, or 4) a combination of some/all the above. I would think that a bait high in rotten meats/fish would definitely contribute to lesser quality of meat. To what degree I don't know.
I think your second question is much more dependent on proximity to humans than the type of bait. If there are houses/cabins nearby that offered a similar and accessible food source there would probably be a much higher likelihood of creating a nuisance bear (i.e. dogfood, horsefeed, etc.). If they are not rewarded with an accessible food source from those areas they aren't likely to become a nuisance bear.