I found Zyprexa to be less sedating. Seroquel caused me to feel this extremely heavy tiredness in the morning.

Seroquel is actually supposed to be more sedating at lower dosages. My doctor explained the paradoxical effect, and I am not certain I'd do the explanation any justice, but lower dosages act as an antihistamine instead of an antipsychotic/mood stabilizer.

It can however take between 5 and 15 mg of Zyprexa to induce that sedating effect.
As above mentioned, Zyprexa is known to be very much linked to weight gain. I did not experience this though.
(I actually found that shortly after drinking Seroquel, my appetite skyrocketed and I ate everything I could get my hands on. This was just my experience)