What people get prescribed depends on a lot of factors — some obvious and others not so much — like psychotropic naiveté vs x number of partial response/failed med trials, pre-existing heath conditions, symptomology, trial and error response to each med weighed against any observable side effects, what a patient's insurance is willing to pay for/not pay for, both the quality and time period of the doctor's medical education, e.g. I've worked with some doctors in their 60's & 70's who much more favored older antipsychotics (toss up on if that's due to believing they're "better" meds vs. that's just what they know). I'm sure there are others I'm blanking on, but I'd say that's a good start.

Also, obviously take it with a grain of salt but also keep it in mind: I've worked on an acute inpatient psych unit for 8 years at a well known and respected psych hospital in MA and with a few exceptions most of the doctors I've worked with don't start with Seroquel as the primary antipsychotic for severe manic/psychotic episodes; it's frequently either Risperdal or Zyprexa. One seen it get used more in the >800mg range for "mood stabilization" or 25mg/50mg/100mg for a non-benzo anxiety and/or sleep med.

Honestly, I think the only antipsychotics that suck more than Seroquel, especially for full blown mania/psychosis are Saphris (which I've seen used < 5x in 8 years and all failed; might actually just be a black cherry flavored tictac) and Abilify (which is like the Zima/Smirnoff Ice of the antipsychotic world).