Count me as a Coast fan. I love that they are cheap and can be included into the cost of the cake, so no returns, no deposits!
A PVC pipe cutter works great for getting the lengths right on the first time, I hate to be sawing pillars! Too much mess! Also, if you drill a 1 1/2" hole in the center of each plastic plate, you can easily drive a sharpened dowel into your foam-core base for horizontal stability.
For years I worked in a bakery of a large catering company, and that is the system we used. We never had a cake fall. And the decorators never got to deliver the cakes themselves! It was always the party servers, most of whom were summer hires, and knew nothing about tranporting wedding cakes!
Occasionally, we would get a cake done in by a case of liquor stacke above and an abrupt slamming on the brakes, or dropped in route to the cake table, but no collapses!
Glad you got the new support system! Now that will be one less thing to worry about!