IME, the long wall presented fewer bass related problems and spread the music around more efficiently.
Wall materials and obviously room layout play a large part, too.
For example, there were notable improvments (in everything, really) when placing my speakers along a long, load bearing brick wall. One was free to lounge about wherever, and still get good music. However, it was domestically impossible to live with due to furniture and room layouts.
I'm now using them against a short room divider, and find that one must be fairly anchored into place to get the best effect especially wrt bass behavior. It's easy to tell by walking the length of the room where the bass humps are.
Clear as mud?