Shorter scale can have more focused punch on single notes but can be a little barky when playing chords. Longer scale typically has more jangle and zing. I really like GDAD over GDAE myself, my approach is usually to use a capo to put the DAD courses into a useful place for the key I'm in, as melodies in keys with fewer open notes get a little stretchy. Though my instrument is a 10 string cittern, 650mm scale, tuned CGDAD.