I need to replace three upstairs windows that have RO of 71" wide x 39-1/2" high. My current windows are two pane sliding windows and both panels can slide.

Looking at replacements (Andersen at HD):

1) I can find sliding windows for just under $600 each but seems only one panel slides.
2) There are casement available in either two or three casements or two casements and a picture window in the middle. These are about $1300 each.

Some say the casements seal better but we never really had any issues with the sliding. Any help choosing window type appreciated.

(also, seems to be 16-18 week wait time on the windows)

Thanks
Mike