I also have never heard the line about vibration hurting the machine. I kind of laugh at that one. How do they think machines get from the factory to the store. There are generally trucks, trains, and boats involved! I do agree that the OP needs to think about where she will be taking the machine and what she wants to take with it. My favorite "case" is actually a plastic tote that I put on a rolling cart. For a number of years I haued my machine to a sewing group every two weeks, rain or snow, carrying fabric and notions. I used the fabric to pad the machine, and the tote kept my machine out of the muck. I would have a different answer if I travelled with my machine on airplanes though.
Pam