Andersen does not use fiberglass. They do have a composite window (Fibrex), however, that is a mostly vinyl window.

I think the Marvin Integrity is a superior window but you are well advised to get a competitive bid on the project.

I would second wow recommendations

Thanks, I have been seen the Integrity in a show room and was impressed. By competitive bid, do you mean different distributors of the same (marvin) windows, or all distributors on the page.....

Same product different dealers using the same specs.

We considered the Integrity, Andersen, Milgard Ultra and a few aluminum windows and eventually settled on the Integrity for our tiny beach house. We are replacing / adding new windows in stages. We put in our first window last week and we'll do two more this weekend. I can't say anything about longevity, but I am happy with the way the window looks as well as our local Marvin dealer. We went with the all Ultrex model with the ebony exterior. IIRC, the Integrity was the only fiberglass window to come in black; the others come in an almost black dark bronze but that would not have cut it as our other trim, front door and garage door are or will all be a true black. My one complaint about the all Ultrex is the lack of grid options--you can only have the fake looking internal grids and the interior side of the grids is only available in white. Since we think we'll eventually paint the interior of the windows black, we didn't want to be stuck with a grid/muntin bar that we couldn't change, so we went with no grids. Our windows are single hung.