As I wonder through the maze of windows it seems like there are two or three window glass manufacturers and what you are then buying is the frame.

On the glass you select what you want, argon, laminate, etc. Once you determine what glass options you want then you go looking for a frame manufacturer. My question is, on a vinyl window, what should one be looking for in terms of a better made product?

I would assume how the joints are put together. But what about the springs that make the window go up and down. A foam filled frame is probably more desirable. Is there some kind of a check list that window installers use to grade a product? Or is the real biggy in finding a manufacturer with a long history and good warranty?

I am having a certified installer do the windows so I've no problems with the way they will be put in. I've been given options with five different windows. Just trying to determine how best to chose the window manufacturer. In the end, is it just by the window you find more pleasing to the eye?