I tried nutmeg for the first time a few weeks ago.  It was indeed like being stoned for over 24 hours.  I had a slight feeling of nausea the entire time, but I would compare it to discomfort from "the munchies".  Overall, the negative effects were minimal compared to the high feeling.  If I had to draw a negative from the experience, it would be that being stoned constantly seemed rather cumbersome after the first day or so.  Space paste may be more powerful, but I imagine that that would only make the long experience even more of an ordeal.