Ok, you asked.. so here goes.
Started with a Viking 1+ and then I bought a Rose, both were doing fine with I traded or sold them after 5 years so that I could upgrade to a larger embroider area. Bought a used Designer 1 and had nothing but problems with it, so I bought a used Brother Disney machine and the computer portion just quit after 3 years. To expensive to replace so I bought a NEW Brother ULT Embroidery machine. After 4 years, the mother board cracked and instead of just replacing it, I traded it in on my Brother Quilt Club 1000 and I have had that one for a long time now. When the others gave out, I was teaching embroidery, so the machines were going and going and going... I also have a Brother Cs1000i, their entry level computerized machine and it is a work horse. Weighs 9 pounds and has traveled with me on air plains and hasn't give me any issues in about 15 years.
Here is what I think the issue is, its not how old the machine is, it is how much does it get used. Mine failed because of the amount of use I gave them, on the other hand, my Quilt Club is a "sewing" machine only and doesn't do embroidery, their TOL machine at the time with all the bells and whistles, and she still purrs like a kitten.
The more they put on them, the more there is to fail.....