I'm in the same boat as one of the previous writers; whichever machine I am sitting at right now is my most favorite in all the world.....
I am an Elna lover from the word go--1959 or so--bought TOL models every few years just because DH would offer to get me a new machine for Christmas. But, since this board came into my life, I have become a "collector" of whatever my eyes lit up on--several FWs, 99Ks, 401A, 301s, Necchi, many Japanese made Singer clones, and the list just keeps on keeping on.
For every day sewing and mending, I always go to my Elna (mid 80s, if I remember right); and whatever FW is set up currently for my quilt piecing; and have a Gammill for my quilting.
Keep on your quest for the 7550 that you have loved all these years. You'll find one. Good luck.