given the application (over sink) both sound about same in terms of air flow --- esp if there are other windows in the area to create the draw and differential pressures... They are just different from each other, especially in terms of the view out. That is where do you want and not want to see the frame? How large is the window opening? There are some casements that have no center vertical bar ... the two windows crank out to create one large unobstructed opening. I have awnings at my sink in a rural cottage and that is perfect because it allows alot of open shelving above and (since we are not very tall folks) we can see out just fine. Sometimes they can be a little more difficult to crank tightly closed however. Where I have casements, I love them but am always conscience of not leaving them wide open lest it rain. Also depending on the height of the window above the sink, you want to consider which is easier to operate, in terms of reaching the hardware.

We went through the Andersen/Pella/Marvin//fiberglass/generic decision process long ago and decided to go with the Andersens because the company has a reputation for standing by their product, they looked fine to us, plus both the contractor and architect recommended them. But now that it's time to order the units, we realize that we have never seen casement or awning 400-series windows with vinyl interiors. We've been to multiple Home Depots multiple times, to two different "WindowRama" places that have pretty good selections of Andersen (and other) models to look at, and also went to an Andersen "super showroom." We've seen and carefully decided on what we want for the 14 double hung windows that we are putting in, and are not too worried about the eight clerestory awnings because they will be so high. There are nine casements, and the five that will be at eye-level in the kitchen are a major concern. As eastbay10 rightly indicates, we dearly want to avoid disaster, and if we can't see the units in person we're thinking we will have to get unfinished pine and paint them ourselves; that's time and expense we'd rather avoid. We're not looking for GardenWeb to make the decision for us, but thought it was worth a shot to see if anyone had any experience they could share with us.

I think installing transom style windows in place of the 1/4 rounds would unify the look with what's over the doors below. The stalagmite trees and mushroom hedges at the entrance were probably originally part of the formal look, but they have outgrown their welcome and your home would benefit from a reno on the landscaping. That's where you could loosen up the formality of the architecture which you're stuck with.

Can you post some pictures of your home?