I've only had 3 sewing machines that got regular usage, and 2 sergers. I also have a cheap Brother "Project Runway" model I picked up at a thrift shop for my granddauther to use when she is old enough, my MIL's ancient Singer which is currently in storage, and a Singer 66 treadle machine. My mother's Singer Rocketeer 503A which I learned to sew on is waiting in wings for my future inheritance.
I have zero brand loyalty to the sergers. First was a Riccar, VERY early in their domestic use. It was only a 3-thread and I had to practically stand on my head to thread it. It lasted 20+ years and by the time I replaced it, Riccar wasn't even an option as far as I could tell and I purchsed a Brother 3034D, in large part because my cousin worked for the dealer. I don't love or hate it. It does the job, but I'd love to get the old one running again just so I can keep one threaded in black and one in white.
My first sewing machine was a Viking, bought used in 1983. The very first purchase of significant cost that I made as an adult with a "real" job. Possibly a model 6030, definitely something of that era and family. It died when I was in the midst of making a collection of doll clothes for my then-5yo for Christmas.
It was replaced by a Pfaff 1467. THAT machine I LOVED. With the single exception of making crappy buttonholes, it was a dream machine. It performed every task I ever asked it to, and all with only about 3 maintenence visits over 20+ yrs. I wore it out. My daughter now has it. She only sews for minor houseshold jobs.
Because I loved the 1467 so much, I replaced it with another Pfaff about 3-4yrs ago. This one is a QE4.2. I do NOT love it like the other. It's too finicky and delicate in its preferences. Lint is way too much of a problem, but it can't be well cleaned out without a spa day. Just found out rather expensively how important that yearly visit is. However while it was in the shop, I still chose to await its return rather than use the other machines as back-up, so I guess there is some level of "love" there. Before I bought this machine, I would have said I was a die-hard Pfaff-only fan, in part because I love the dual feed and they used to be the only brand that had that. Were I to go machine shopping again, I'd look at other brands that now have the dual feed.
I'm keeping my eyes open for a used Viking of the same era as my first machine. That machine made gorgeous 4-step buttonholes that neither of my Pfaffs have been able to come close to.