Think your eaves are designed correctly? Fat chance. Few builders know how to get them right, and the errors don't just look stupid (once you know what's better) but they can rot your gutters as well. And what's the quickest way to make part of your house look like Dumbo? Yep… get the dormer proportions wrong, just like 95% of your neighbors do.
Round gutters are better than ogee gutters because when ogee gutters overflow, they trap water against the fascia, eventually rotting it, whereas round gutters let the water fall away.