If you look at the quarter window in this picture, you can see one of the curvature issues. The fact that my rear clip isn't on correctly exacerbates the issue, but the curvature does not match. The front doesn't curve in properly, but the entire window is basically flat, then put on a curved surface. This results in odd flat spots at various places on the window itself. Also, the window bulges a bit away from the B-pillar, resulting in airflow (and debris) getting between the B-pillar and the window. Eventually, the debris, or potentially ice could cause the window to come loose.
These are aftermarket windows from a known vendor.
Some day, I'll get the rear clip put on correctly, which will help several issues.
Edit: Oops.