I do not have one, but my girlfriend has several. The sides are just the material although they do have an extra pocket on the outside, so I guess you could call that "some" padding. They zip open so a machine can be put in sideways if you need to or from the top. The outer frame is very sturdy and holds the machine in place. She has had hers for years and has never had a machine have any issues. NOTE: The biggest one has to be loaded by either a strong man or two women.
This All brands site shows a lot about the rolling trolleys.
http://www.allbrands.com/products/93...6%20Embroidery]
Edited to add: This is just one of the sizes that is available.