Both Janssen and Eli Lilly are now recommending much more gradual crossovers, up to six months if the individual is switching from a depot medication. Generally there are two types of atypicals available at the moment, the ones like Risperidone and the ones like Clozapine. But it's fair to say they are each quite different from one another. Atypicals by definition do not cause EPS side effects and they alleviate negative symptoms by stimulating prefrontal cortex activity. They also have mood stabilizing qualities and reduce suicidal behaviour.
Cognitive scores improve on atypicals as well although that research is just beginning.
Used early in the illness they also prevent cognitive deterioration. Clozapine is considered the best for the treatment refractory. Other people don't usually get to try it. It was the first atypical, developed in the sixties I think, but taken off the market in the seventies when it was found to be responsible for a number of deaths from agranulocytosis. It was reapproved in 1991, when research showed it was the only drug that worked with the treatment refractory with the condition of regular blood sampling to prevent agranulocytosis.